30 July 2023, Volume 54 Issue 7

    

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Focuses & Concerns (The Project of Chongqing Press Fund in 2022)
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  Experimental study on frost resistance of 3D printed recycled coarse aggregate concrete

  LIU Chao, ZHANG Zhining, LIU Huawei, ZHANG Wei

  Jorunal of Functional Materials. 2023, 54(7): 7001-7009. https://doi.org/10.3969/j.issn.1001-9731.2023.07.001

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  3D printing technology has been significantly developed in the construction field, and in order to address the concrete 3D printing industry to achieve sustainable development, this paper analyzes the causes of deterioration by conducting freezing resistance studies on 3D printed specimens and cast specimens with 0%, 50%, and 100% recycled coarse aggregate (RCA) substitution, combined with electron microscopy scans of the transition zone at the interface of 3D printed recycled coarse aggregate concrete (3DPRAC). The results showed that the incorporation of RCA in the first 200 freeze-thaw cycles did not significantly reduce the mass and dynamic modulus of 3D printed concrete; after 600 freeze-thaw cycles the 3D printed recycled concrete with 100% RCA incorporation performed better than that with 50% RCA incorporation in the freeze-thaw cycles. Based on the construction characteristics of 3D printed recycled concrete stacked layer by layer, a 3DPRAC pore area concentration distribution model was proposed to reveal the 3DPRAC freeze-thaw damage deterioration mechanism. The established freeze-thaw damage model can better reflect the change pattern of 3DPRAC freeze-resistance performance.
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  Synthesis and magnetic induction characteristic of low-loss ZrO₂@CIPs soft magnetic composites with core-shell structure

  LIU Yiying, ZHOU Sheng, CHU Qiyuan, HE Sizhe, FEI Jiangwei, ZHANG Yong, HUANG Hao

  Jorunal of Functional Materials. 2023, 54(7): 7010-7017. https://doi.org/10.3969/j.issn.1001-9731.2023.07.002

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  The surface modification of carbonyl iron powders (CIPs) was carried out by using zirconium butoxide (TBOZ) solution. Zirconium dioxide coated carbonyl iron powders (ZrO₂@CIPs) composites with different zirconium content were synthesized by adjusting the amount of TBOZ. The static magnetic properties and insulating properties of CIPs and ZrO₂@CIPs composites have been investigated, and it has been shown that ZrO₂ can effectively suppress the deterioration of the static magnetic property of CIPs when the temperature is increased to 200 ℃. Meantime, the resistivity of ZrO₂@CIPs composites has been greatly improved. Comparing the magnetic loss capacity of CIPs and ZrO₂@CIPs composites, it can be found that the magnetic loss capacity and DC bias properties of ZrO₂@CIPs composites are improved with increasing the amount of TBOZ. When the amount of TBOZ is 15.57 mL, the μ″ of ZrO₂@CIPs composites is only 0.05, quality factor is 116.7, and the rated current is 17.10 A. In addition, compared with CIPs (-0.91 V), the corrosion potential of ZrO₂@CIPs composites is increased to -0.33 V, demonstrating the enhanced corrosion resistance. In general, the results of this work can be served as a reference for the modification of conventional CIPs in the inductance domain.
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  Effect of anisotropic plane of titanium dioxide on supercapacitor performance

  WANG Xiaodong, ZHANG Yanyany, XU Chunxiang, WANG Hongxia, ZHANG Wanggang, LI Taotao

  Jorunal of Functional Materials. 2023, 54(7): 7018-7025. https://doi.org/10.3969/j.issn.1001-9731.2023.07.003

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  In this paper, the effect of grain anisotropy on the electrochemical performance of anatase TiO₂ was studied, which is significant for the improvement of supercapacitor material performance. Using hydrothermal synthesis, HF and H₂SO₄ were used as different acid morphology inducers, and tetrabutyl titanate was used as titanium source to prepare TiO₂ in the form of platy and spherical microcrystals, which exposed different crystal faces. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that the crystal faces exposed by platyt TiO₂ were highly active {001} planes, while the crystal faces exposed by spherical TiO₂ were random. X-ray photoelectron spectroscopy (XPS) and specific surface and porosity analysis (BET) and corresponding electrochemical performance tests were used: the results showed that the specific surface area of platy TiO₂ (112.76 m²/g) was 2.41 times that of spherical TiO₂ (46.88 m²/g), and the specific capacitance of platy TiO₂ supercapacitor (174.0 F/g) is a spherical TiO₂ supercapacitor specific capacitance (67.0 F/g), while platy TiO₂ supercapacitors exhibit higher cycle stability than spherical TiO₂ supercapacitors. The excellent performance of platy TiO₂ is mainly attributed to the high specific area and exposed highly active {001} crystal planes.
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  Magnetic properties of SrFe₁₂O₁₉ prepared by microwave assisted molten salts method

  LIU Lin, LIU Jianxing, YANG He

  Jorunal of Functional Materials. 2023, 54(7): 7026-7031. https://doi.org/10.3969/j.issn.1001-9731.2023.07.004

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  In this experiment, SrFe₁₂O₁₉ was prepared by microwave assisted molten salt method used iron oxide red as iron-bearing raw material which is secondary product of steel plants. The effects of Fe/Sr molar ratio and microwave calcination temperature on the phase composition, microstructure and magnetic properties of the samples were studied. The XRD data of the samples were refined and fitted by the FullProf program, the morphology of the samples was observed by scanning electron microscope (SEM), and the magnetic properties of the samples were characterized by vibrating sample magnetometer (VSM). The results showes that the Fe/Sr molar ratio has an important influence on the phase com-position and the cell parameters of the sample. When the Fe/Sr molar ratio is 10.5, the sample has better magnetic properties. With the increase of calcination temperature, the thickness of SrM phase also increases. The thickness of SrM phase is the largest after microwave calcination at 1373.15 K for 2 hours. At this time, the maximum coercivity force of the sample reaches 2.69×10⁵ A/m, and the saturation magnetization is 63.04 A·m²/kg. The maximum magnetic energy product of SrM prepared at 1 273.15 K is 9.47×10³ J/m³.
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  Simple preparation and oil/water separation performance of hydrophobic KH550-TiO₂@PDMS@PU sponge

  WANG Xinge, YUAN Zhangfu, ZHAO Linfei, YANG Xiao

  Jorunal of Functional Materials. 2023, 54(7): 7032-7041. https://doi.org/10.3969/j.issn.1001-9731.2023.07.005

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  Oily wastewater is generated inevitably in the production processes of iron and steel products. It poses a threat to the environment and consequently to human health if not handled properly. In this study, a hydrophobic and oleophilic KH550-TiO₂@PDMS@PU modified sponge was prepared by a simple one-step impregnation method. TiO₂ nanoparticles, 3-aminopropyltriethoxysilane (KH550), and polydimethylsiloxane (PDMS) were the main starting chemicals. Due to the low surface energy of PDMS and the rough structure caused by the KH550-modified TiO₂ particles, the sponge was converted to a hydrophobic material and the water contact angle was (147.25±1.44)°. The modified sponge could maintain stable hydrophobicity and durability under complicated conditions such as gluing, extrusion, acid and alkali, and ultrasonication. It could absorb oil up to 20-25 times its own weight by means of the adsorption-extrusion cycle. The excellent oil/water separation performance suggests that the KH550-TiO₂@PDMS@PU sponge with advantages of being non-toxic, easy to prepare, stable and hydrophobic has a broad application prospect in the steel industry.
Review & Advance
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  Research progress in thermal endurance of sugar alcohols phase change materials

  WUSIMAN Kuerbanjiang, DAI Xiaoye, SHI Lin

  Jorunal of Functional Materials. 2023, 54(7): 7042-7049. https://doi.org/10.3969/j.issn.1001-9731.2023.07.006

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  Sugar alcohols as a type of intermediate temperature phase change materials(PCMs) have been attracted considerable attention in thermal storage for their good comprehensive performances comparing that with inorganic and other organic materials base on their higher fusion enthalpy. However, there are few industrial applications of sugar alcohols as PCMs at present. The main reasons except their ubiquitous defects, such as severe supercooling, relative low thermal conductivity, the thermal endurance of the fusion enthalpy is a key fundamental factor in their practical application, which is little attention paid to that by most of previous studies. In this article,the research progress in focusing on thermal endurance of the enthalpy for sugar alcohols, such as the causes of degradation, related mechanism, experimental measures for improvement, kinetics-predictive model and melting point regulation for lifetime expectancy were reviewed in recent years. It provides ideas and methods for reevaluating the feasibility of sugar alcohols as PCMs, and also provides a research direction for their practical application.
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  Application of carbon quantum dots in photocatalytic degradation of organic pollutants in water

  JIN Yanling, REN Penggang, WANG Jiayi, GENG Jiahui, CHEN Zhengyan, REN Fang, SUN Zhenfeng

  Jorunal of Functional Materials. 2023, 54(7): 7050-7059. https://doi.org/10.3969/j.issn.1001-9731.2023.07.007

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  Photocatalytic technology is an effective way to solve the two major problems of environmental problems and energy crisis. The development of efficient photocatalysts has become a research hotspot in this field. As new type of carbon nanomaterial, Carbon quantum dots (CQDs) have garnered much attention in the field of photocatalysis because of their unique up-conversion luminescence and excellent photogenerated electron transfer properties. In this paper, the mechanism of photocatalytic degradation of pollutants and the properties of carbon quantum dots was introduced, the research progress of photocatalytic degradation of organic pollutants in water by carbon quantum dots was reviewed with emphasis, followed by an outlook on their future and potential development.
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  Study of bismuth-based photocatalyst for degradation of organic wastewater

  HE Yingxiang, LI Adan

  Jorunal of Functional Materials. 2023, 54(7): 7060-7068. https://doi.org/10.3969/j.issn.1001-9731.2023.07.008

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  Pollution of water resources is seriously endangering human health. Bismuth-based photocatalytic materials also show great potential in controlling organic pollution, with the advantages of green, efficient, clean and low cost. This paper briefly introduces the research progress of various bismuth-based photocatalytic materials in the degradation of organic wastewater, summarizes the modification methods of various bismuth-based photocatalysts and the degradation effects of various organic pollutants, and analyzes the factors affecting the efficiency of bismuth-based photocatalytic materials in the degradation of organic compounds in water. The future development of photocatalysis in the degradation of organic wastewater was also explored, and several proposals for the development of bismuth-based photocatalysis materials were presented.
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  Recent developments and design strategies of electrocatalyts in ammonia synthesis

  WANG Ruyi, HU Guoyan, WANG Xue, GUO Zhongcheng, HE Yapeng

  Jorunal of Functional Materials. 2023, 54(7): 7069-7079. https://doi.org/10.3969/j.issn.1001-9731.2023.07.009

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  Traditional industrial ammonia production mainly comes from the Haber-Bosch method operated under high temperature and pressure, which requires high energy consumption and brings about large pollution. With electric energy as energy source and water as proton/electron source, nitrogen could be reduced to ammonia via the synergistic effect of voltage and catalyst. The electrocatalysis ammonia technology has gradually developed into one of the effective ways in ammonia synthesis. The key to the electrocatalytic ammonia synthesis technology is the design of catalysts and optimization of reaction systems. The reasonably design of high-efficiency electrocatalysts is considered as important approach to optimize the production kinetics and Faradaic efficiency. Here, the paper describes the primary classifications and research progress of electrocatalysts, which mainly include noble metal, transition metal, single-atom and non-precious metals. Then, the development of ammonia synthesis technology and reaction mechanism during the electrocatalytic ammonia production are elaborated. Moreover, the strategies for improving the activity in electrocatalytic ammonia production are reviewed, including surface morphology optimization, crystal defect engineering, composite material composition, phase interface, addition of additives, etc. Finally, the issues and challenges as well as development trends in the future are prospected.
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  Research progress on surface modification technology of flexible electronic polymers

  ZHANG Chao, MA Xun, WANG Jingjng, LIU Ping, MA Fengcang, ZHANG Ke, LI Wei

  Jorunal of Functional Materials. 2023, 54(7): 7080-7092. https://doi.org/10.3969/j.issn.1001-9731.2023.07.010

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  Flexible electronic devices are widely used in radio-frequency communication antennas, sensor detection, medical health, microelectronics, and other fields. On account of the low density, extremely high flexibility, and deformability of polymers, they can satisfy the requirement of flexible electronic devices for customization and versatility. Besides, the further development was restricted to the low conductivity and poor mechanical properties of flexible polymers, based on the above challenges, there has been an increased research focus on the representative of modern technology such as electroless plating, laser molding, and vacuum deposition, which provided the significant solutions for surface patterning, miniaturization, and customization for flexible electronic device. This review summarizes the research progress of surface metallization processes of flexible polymers in recent years, and the fundamental principles and the rules of these techniques are discussed along with the process parameters and indicated the strengths and weaknesses, followed by an exploration of the latest progress and future prospects in the field.
Research & Development
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  Effect of rare earth Y, La and Sm doping on dielectric properties of barium titanate ceramics

  ZHANG Yunfei, LIANG Bo, WAN Qitong, ZHANG Mengya, HUANG Qiwei, BING Lina, SHEN Zhenjiang

  Jorunal of Functional Materials. 2023, 54(7): 7093-7100. https://doi.org/10.3969/j.issn.1001-9731.2023.07.011

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  Stable dielectric constant and low dielectric loss are important parameters to evaluate the dielectric quality of materials. In this study, three rare earth elements Y, La and Sm were doped into the analysis of pure barium titanate by labring-annealing process, and the dielectric properties of barium titanate doped in different proportions were evaluated, and good results were obtained. Three groups of samples with doping ratio of 2 mol%, 4 mol%, 6 mol%, 8 mol% and 10 mol% were prepared and characterized, and dielectric loss measurement and dielectric constant calculation were carried out. The results show that pure grade barium titanate doped with these three rare earth elements has better crystallization and does not inhibit the growth of grain. In the three groups of samples, the B-site was mainly doped to form oxygen vacancy compensation, which inhibited the electron concentration and effectively reduced the dielectric loss, and the stability was better in the full frequency range, less than 0.05. Compared with pure barium titanate ceramics, the dielectric constant decreased from 1500-1600, and the minimum dielectric constant of La doped titanate was 100-400. This research can provide reference for barium titanate in the production and application of actual components.
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  Compressive properties of hybrid fiber engineered cementitious composites after high temperature

  ZHOU Zongbo, CHEN Zexin, YU Zhihui, ZHANG Cong

  Jorunal of Functional Materials. 2023, 54(7): 7101-7107. https://doi.org/10.3969/j.issn.1001-9731.2023.07.012

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  The compressive properties of single-doped polyvinyl alcohol ( PVA ) fiber engineered cementitious composites ( PVA-ECC ), steel fiber/PVA fiber hybrid ECC ( HyFRECC ) and steel fiber/PVA fiber/calcium carbonate whisker hybrid ECC ( MsFRECC ) at room temperature and 200, 400, 600 and 800 ℃ were compared and studied. The results showed that the compressive strength, compressive toughness and elastic modulus of the specimens could be improved by adding steel fiber or both steel fiber and calcium carbonate whisker at room temperature. Under the action of 200 ℃, due to further hydration inside the cementitious composites, the compressive strength of the material would be improved significantly, while the improvement of compressive toughness was not obvious. When the temperature exceeded 200 ℃, the compressive strength and compressive toughness of the material continued to decay, but the steel fiber and calcium carbonate whiskers played a beneficial role in improving the compressive strength and toughness after the peak, the MsFRECC group had the best compressive properties in each group, which indicated that the hybrid incorporation of steel fiber and calcium carbonate whisker was able to improve the compressive properties of cementitious composites after high temperature significantly. The compressive properties of each group had little difference after 800 ℃, the residual strength and toughness were less than 45%.
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  Study on the growth mechanism of SiC fiber catalyzed by NiCl₂ and its microwave absorption

  HAO Wending, ZHANG Xiyue, WANG Gaoyuan, ZHANG Jingbo, GUAN Li, ZHANG Rui

  Jorunal of Functional Materials. 2023, 54(7): 7108-7114. https://doi.org/10.3969/j.issn.1001-9731.2023.07.013

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  Using industrial coal and ethyl orthosilicate as raw materials and NiCl₂ as catalyst, the microwave-induced catalyst was used to synthesize SiC fibers. The effects of catalyst concentration and temperature on SiC fibers were discussed, and the microwave-absorbing properties of SiC fibers were studied. The products were characterized by X-ray diffraction, field emission scanning electron microscope and vector network analyzer. The results show that various morphologies of SiC can be formed by NiCl₂ catalyst with different concentration. When the catalyst concentration is 5%, nano- SiC fibers can be formed. SiC can be prepared by microwave heating at 900 ℃ for 30 min under the action of 5% NiCl₂ catalyst. The magnetic linear Si-Ni compounds formed during the preparation process can promote the rapid formation of SiC fibers. When the thickness of SiC fiber is 4mm and the frequency is 4.06 GHz, the RL of SiC fiber reaches -36.74 dB, showing excellent electromagnetic wave absorption performance. The results provide theoretical and experimental basis for microwave induced preparation of high performance wave absorbing SiC fibers.
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  Single crystal growth and electromagnetic resistance effect of topological semimetal FeSn₂

  WU Lin, WANG Sheng, CHEN Haoze, CHENG Li, ZOU Yuchen, ZHOU Wenjie, ZHANG Li

  Jorunal of Functional Materials. 2023, 54(7): 7115-7118. https://doi.org/10.3969/j.issn.1001-9731.2023.07.014

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  FeSn₂ single crystal with the size of approx. 2 mm×0.8 mm×0.8 mm was synthesized by flux and vapor transporting method. XRD and EDS analysis show that the ratio of Fe: Sn in single crystal is 33.3%∶66.7%=1∶2. PPMS and MPMS analysis showed that the resistance effect of FeSn₂ was as follows: (1) Residual resistivity of FeSn₂ RRR is 320; (2) FeSn₂ exhibits non-Fermi liquid behavior; (3) It does not conform to the Kohler criterion. The magnetoresistance effects of FeSn₂ is as follows: (1) Single crystal of FeSn₂ has a unsaturated large magnetoresistance, i.e. the MR is 6.8 when the magnetic field is 6.4×10⁶ A/m; (2) It also has a large angular magnetoresistance, i.e. the MR is 6.7 when the angle between B and I is 90 degrees and the magnetic field is 6.4×10⁶ A/m; (3) The obvious sdH oscillation is observed within the low-temperature range (2-10 K). These remarkable topological transport characteristics prove in experiment that single crystal FeSn₂ is topological semi-metal material and its special electromagnetic resistance effect is expected to be used in low -energy-consumption electronics in future.
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  Study on high volumetric specific capacity flow batteries with manganese dioxide semi-solid electrodes

  DONG Yunhe, LIU Chang, YANG Jianhua, LIU Yu

  Jorunal of Functional Materials. 2023, 54(7): 7119-7125. https://doi.org/10.3969/j.issn.1001-9731.2023.07.015

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  Manganese dioxide (MnO₂) is widely used in aqueous zinc-manganese batteries due to its high abundance and low cost. Flow batteries can realize the decoupling of energy component and power component, thus they have been paid more attention in the field of long-term large-scale energy storage. In this study, semi-solid electrodes were designed with MnO₂ as the active substance, and a high volumetric specific capacity flow battery was designed. Firstly, semi-solid electrodes were prepared using Xanthan gum as suspension matrix and Ketjen Black as conductive agent, and the optimal ratio of MnO₂ semi-solid electrodes was determined by characterizing the electrochemical properties and rheological properties of the electrodes. The critical concentration for conductivity percolation of Ketjen Black is 9 g/L, and the semi-solid electrodes prepared with this concentration show good rate performance and cycling stability. The volumetric specific capacity of the semi-solid electrodes can reach 32.5 Ah/L with 300 g/L MnO₂. Semi-solid electrodes exhibit non-Newtonian rheology with a yield stress of approximately 2 Pa which can maintain the mechanical stability of the suspensions while the pumping energy loss is low. The volumetric specific capacity of zinc-manganese flow battery with semi-solid electrodes can reach 22.3 Ah/L, showing promising prospects for development.
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  Preparation of g-C₃N₄ modified by sulfuric acid and its photocatalytic performance for hydrogen production

  CHEN Shuhang, HAO Yachao, ZHAO Yangcan, PAN Yang, WANG Siyan, XU Hongyan

  Jorunal of Functional Materials. 2023, 54(7): 7126-7130. https://doi.org/10.3969/j.issn.1001-9731.2023.07.016

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  g-C₃N₄ was modified by sulfuric acid hydrothermal treatment. The morphology and properties of the materials were tested using scanning electron microscopy, X-ray diffractometer, UV-visible diffuse reflectometer, surface area meter and electrochemical workstation. The morphology, structure and specific surface area of sulfuric acid with different concentration were studied to further explore the reasons affecting the performance of photocatalytic hydrogen production. The results show that g-C₃N₄ treated with 0.4 mol/L sulfuric acid has excellent specific surface area, pore size and visible light response, which leads to high photocatalytic hydrogen production performance. However, when the concentration of sulfuric acid is greater than 0.4 mol/L, the structure of g-C₃N₄ changes and is severely removed, resulting in the reduction of mesoporous pores, which is not conducive to photocatalytic hydrogen production.
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  Ca₃MgSi₂O₈ ceramics: sintering behaviour, lattice vibration, and dielectric properties

  DENG Lian, YANG Qinglan, HE Yinghan, WEI Xiaoli, WEI Xiaopeng, ZHANG Hailin, ZHOU Huanfu

  Jorunal of Functional Materials. 2023, 54(7): 7131-7138. https://doi.org/10.3969/j.issn.1001-9731.2023.07.017

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  The monoclinic Ca₃MgSi₂O₈(CMSO) ceramics were prepared by the traditional solid-state reaction method. XRD showed that CMSO sintered at 1350-1425 ℃ were all single-phase structures with space group of P2₁/a, and SEM found that when the sintering temperature was 1400 ℃, CMSO ceramics had the best surface topography and excellent microwave dielectric properties: ε_r=13.62, Q×f = 42 292 GHz, τ_f=-48.36×10^-6/℃. The relationship between Q×f values and fill fractions and covalent bonds of CMSO ceramics was discussed. The influence of lattice vibration on the internal dielectric loss of CMSO was studied by Raman spectroscopy, and the octahedral distortion of MgO₆ was calculated, which explained the internal mechanism of τ_f change. In summary, CMSO ceramics have good application prospects in the fields of mobile communication base stations, satellite navigation and radar communications.
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  Construction and photocatalytic performance of Z-scheme C-TiO₂/Pt/g-C₃N₄ photocatalyst

  LU Zhao, WEI Huixin, SONG Wulin

  Jorunal of Functional Materials. 2023, 54(7): 7139-7144. https://doi.org/10.3969/j.issn.1001-9731.2023.07.018

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  The g-C₃N₄ nanosheet was synthesized by thermal condensation method, using urea as precursor. Then, the Pt nanoparticles and the C-TiO₂ nanoparticles were growth on the surface of the g-C₃N₄ by thermal reduction method and hydrothermal method successively. Thus, Z-scheme C-TiO₂/Pt/g-C₃N₄ photocatalyst was prepared successfully. Its morphology, structure and optical properties were analyzed by a variety of characterization methods, its photocatalytic degradation properties of MO and TC in visible light were also evaluated. The results showed that the photocatalyst exhibited excellent degradation performance for these two kinds of pollutants, which was mainly attributed to the strong absorption ability of visible light, the high separation efficiency of photogenerated electron-hole pairs, the strong reducibility of photogenerated electrons and the strong oxidation of photogenerated holes. In order to further explore the photocatalytic mechanism, ESR test was conducted on the C-TiO₂/Pt/g-C₃N₄ photocatalyst. The result showed that ·OH and ·O^-₂ with strong oxidation played an important role in the photocatalytic process.
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  Graphitization of polyimide catalyzed by nickel acetylacetone and its thermal conductivity

  LUO Xuliang, WU Jiahao, LIU Jin, WANG Ziqing, MIN Yonggang, LIU Yidong

  Jorunal of Functional Materials. 2023, 54(7): 7145-7151. https://doi.org/10.3969/j.issn.1001-9731.2023.07.019

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  Polyimide (PI) material has become a hot precursor for the preparation of graphite cooling film in recent years because of its six-membered ring molecular structure and high carbon content. As a transition metal element, nickel is often used as the substrate for graphene catalytic growth. Doping nickel in the polyimide substrate can effectively improve its carbonization and graphitization degree and improve its thermal conductivity. However, pure nickel metal particles will deposit in the precursor of PI, polyamide acid (PAA), which makes it difficult to disperse uniformly. In this work, the PI composite film was prepared by adding a metal complex soluble in organic solvent, nickel acetylacetone (Ni(acac)₂), into the PI matrix and graphitized at 2 700 ℃ to obtain a graphite film. The nickel obtained from the decomposition of Ni(acac)₂ at high temperature can promote the carbonization of polyimide, and its solubility in organic solvent also significantly improves the dispersion of nickel in the PI matrix. Finally, the polyimide carbon film with a flat surface was prepared, and its thermal conductivity can reach 782 W/(m·K), which is 30 times higher than that of the carbon film prepared by pure PI. The purpose of this paper is to analyze the carbonization process of polyimide catalyzed by metal complex Ni(acac)₂ and the final carbon film structure, and explore the possibility of finally preparing high thermal conductivity graphite film.
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  Effects of different defects on the electronic structure and optical properties of two-dimensional MoSi₂N₄

  WANG Guang, HUANG Zhechen, LUO Zijiang, GUO Xiang, WANG Yi

  Jorunal of Functional Materials. 2023, 54(7): 7152-7157. https://doi.org/10.3969/j.issn.1001-9731.2023.07.020

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  Two-dimensional materials exhibit immense latent capacity in many domain with excellent performance, and monolayer MoSi₂N₄ materials have non-magnetic semiconductors and good stability. In this paper, first principles calculations based on density functional theory are used to study the photoelectric properties of intrinsic two-dimensional MoSi₂N₄ in nitrogen, silicon and molybdenum vacancies. The results show that compared with the intrinsic two-dimensional MoSi₂N₄, the band gap of the defective structure of the outer nitrogen and molybdenum atoms is greatly reduced, while the band gap of the inner nitrogen and silicon atomic defect structures is 0.781 eV and 0.736 eV, respectively. Moreover, the inner nitrogen defect changes the conduction type of two-dimensional MoSi₂N₄ from the original P-type to N-type semiconductor. Optical properties: Each defect structure causes different degrees of redshift in 2D MoSi₂N₄. Two-dimensional MoSi₂N₄ has excellent material properties, and the study of optoelectronic properties is of great significance for the new generation of optoelectronic devices.
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  Study on preparation and durability of fine mineral powder concrete

  QIN Xiuyun

  Jorunal of Functional Materials. 2023, 54(7): 7158-7164. https://doi.org/10.3969/j.issn.1001-9731.2023.07.021

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  With S95 grade fine mineral powder as the additive, the concrete with different doping amount of fine mineral powder (0,5wt%, 10wt%, 15wt%, 20wt%) was prepared. Through XRD,SEM,mechanical properties,frost resistance and electrical flux test,the influence of fine mineral powder doping on concrete performance was analyzed. The results showed that the addition of proper amount of fine mineral powder accelerated the hydration reaction,promoted the consumption of cement clinker, improved the compactness of concrete, and reduced the number of cracks and pores.With the increased of fine mineral powder, the compressive strength and flexural strength of concrete increased first and then decreased,when the content of fine mineral powder was 15wt%,the compressive strength and flexural strength of concrete reached the maximum,which were 40.1 and 5.79 MPa respectively.The peak compressive stress of concrete increased first and then decreased with the increase of fine mineral powder doping,and the peak compressive stress of concrete doped with 15wt% fine mineral powder was the largest.The frost resistance of concrete was improved by adding appropriate amount of fine mineral powder.When the number of freeze-thaw cycles reached 100, when the amount of fine mineral powder was 15wt%,the maximum relative dynamic modulus of elasticity of concrete was 82.48%, and the minimum mass loss rate was -0.282%, its frost resistance was the best.The electrical flux of concrete decreased first and then increased slightly with the increase of fine mineral powder doping.The lowest electrical flux of concrete doped with 15wt% fine mineral powder was 1914C, and its chloride ion penetration resistance was the best. According to the comprehensive analysis of strength and durability,the best doping amount of fine mineral powder is 15wt%.
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  Preparation and denitrification performance of Cu based SAPO-34 catalyst

  LYU Yajing, GOU Liyuan, PENG Yu

  Jorunal of Functional Materials. 2023, 54(7): 7165-7170. https://doi.org/10.3969/j.issn.1001-9731.2023.07.022

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  The Cu-SAPO-34 catalyst was prepared using morpholine as a template using in-situ hydrothermal method. The catalytic reduction ability of the molecular sieve catalyst for NO was investigated on the catalyst evaluation device. The effects of Si source amounts with different molar ratios on the microstructure, lattice structure and catalytic activity of Cu-SAPO-34 were tested using XRD, SEM, NH₃-TPD and H₂-TPR analysis methods. The results indicated that the grains of Cu-SAPO-34 molecular sieve particles had a uniform and regular cubic structure, with particle sizes ranging from 15 to 30 μm. Excessive or insufficient Si source molar ratio could affect the crystallinity of Cu-SAPO-34 catalyst. At a temperature of 250 ℃, the denitrification activity of the Cu-SAPO-34 catalyst with a Si source molar ratio of 0.3 reached a maximum of 86%. When the temperature exceeded 300 ℃, the denitrification activity of Cu-SAPO-34 catalyst began to decrease. When the temperature reached 600 ℃, the retention rate of Cu-SAPO-34 with a Si source molar ratio of 0.3 reached 81.4%. The Cu-SAPO-34 catalyst had excellent high-temperature resistance and a wide operating temperature. The total hydrogen consumption first increased and then decreased with the increase of Si source molar ratio. The Cu-SAPO-34 catalyst with a Si source molar ratio of 0.3 had a maximum total hydrogen consumption of 415.61 mmol/g and a maximum total NH₃ desorption of 1.56 mmol/g. Overall, Cu-SAPO-34 with a Si source molar ratio of 0.3 has the highest activity.
Process & Technology
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  Preparation and anticoagulant properties of polyallylamine/dopamine covalently fixed phosphorylcholine coating on cobalt chromium surface

  ZHAO Linlin, DONG Xufeng, QI Min

  Jorunal of Functional Materials. 2023, 54(7): 7171-7179. https://doi.org/10.3969/j.issn.1001-9731.2023.07.023

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  Dense mesh stent is the first choice for the treatment of giant aneurysms. However, due to the dense mesh and abnormal hemodynamic conditions after implantation, the risk of thromboembolism increases. Surface grafting of phosphorylcholine (PC) can improve the anticoagulant performance of implanted stents, but the preparation process of traditional biomolecular coupling method is complex. In this study, amino-rich coating (PDA/PAa) was constructed by grafting polyallylamine (PAa) on the surface of dopamine (PDA) coating through Schiff base reaction and Michael addition under alkaline condition. 2-methacryloyloxyethyl phosphorylcholine (MPC) was covalently fixed on the surface of the amino-rich coating by Michael addition reaction. The PDA/PAa/MPC coating was successfully fabricated by X-ray photoelectron spectroscopy (XPS). The results of platelet adhesion test and whole blood test showed that the PDA/PAa/MPC coating had good anticoagulant activity. Cell experiments showed that the PDA/PAa/MPC coating had good cytocompatibility and could inhibit the adhesion and proliferation of smooth muscle cells (A7r5).
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  Preparation of magnetic iodine-containing biochar and its application in water treatment

  WANG Junhong, MO Fengmin, ZHANG Yingxing, ZHANG Jielan, TIAN Guanghui

  Jorunal of Functional Materials. 2023, 54(7): 7180-7185. https://doi.org/10.3969/j.issn.1001-9731.2023.07.024

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  Taking agricultural waste straw as raw material, magnetic biochar was first prepared by pyrolysis, and then magnetic iodine-containing biochar nanocomposites with photo-response were prepared by solvothermal method. In order to test the application effect of the prepared materials, the adsorption and photocatalytic degradation of the dye rhodamine B (Rh B) in water were studied using the prepared materials as adsorbent and photocatalyst. The results show that the prepared composite has the structural characteristics of magnetite Fe₃O₄. After combining with iodine, the saturation magnetization of the sample decreases, but it can still be absorbed by the external magnetic field. The prepared samples have larger specific surface area, total pore volume and larger pore size. The material has an irregular shape and structure, and elements such as Fe, O and I are evenly distributed in the matrix structure of the main biochar. The results of adsorption- photocatalysis experiments show that the prepared composite has high adsorption and photocatalysis properties, making the maximum degradation rate of Rh B reach 94.71%. It realizes the purpose of “turning waste into treasure” and “treating waste with waste”, and provides methods and guidance for the effective utilization of other agricultural and forestry wastes and urban garbage, which has a good practical application prospect.
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  Preparation and properties of tetradecanol@polyaniline microencapsulated phase change materials

  LIN Chuanhuang , SUN Sailing , NING Yuhao , TAN Ye , YU Linping , ZENG Julan , YU Saibo

  Jorunal of Functional Materials. 2023, 54(7): 7186-7192. https://doi.org/10.3969/j.issn.1001-9731.2023.07.025

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  Microencapsulated phase change materials (MePCMs) with polyaniline (PANI) as shell material are a kind of important multifunctional MePCMs. In order to broaden the source of functionalized MePCMs with PANI shell, in this work, tetradecanol (TD) was selected as core material and a series of TD@PANI MePCMs were prepared via a simple surface polymerization of aniline in the TE/water suspension. The effects of emulsifiers and core shell mass ratio on the properties of the prepared MePCMs were investigated. The results showed that the addition of emulsifier was unfavorable to the formation of TD@PANI MePCMs. The encapsulation ratio and spherical regularity of the obtained MePCMs prepared in the reaction system without emulsifier were increased first and then decreased with the increase of the core shell mass ratio, and the best result was obtained when the core shell mass ratio was 4.8∶5.2. The onset phase change temperature of the MePCM prepared under optimal condition was 32.44 ℃ with a phase change enthalpy of 102.3 J/g and a encapsulation ratio of 46.4%. Besides, the prepared MePCM possesses good thermal stability. In addition, the chemical properties and crystal structure of the tetradecanol core material did not change after it being microencapsulated by PANI. The results of this study can build a solid foundation for the development of multifunctional MePCMs with PANI shell.
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  Preparation and performance of waterborne epoxy resin intumescence fire retardant coatings

  SUN Peng, CUI Kaiyuan, ZHANG Cheng, OUYANG Mi

  Jorunal of Functional Materials. 2023, 54(7): 7193-7199. https://doi.org/10.3969/j.issn.1001-9731.2023.07.026

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  The effect of each component and its additive amount (mass fraction/%) on the fire resistance of waterborne epoxy resin intumescence fire retardant coating were studied. For intumescent flame retardant (IFR): the orthogonal experiment of ammonium polyphosphate (APP), mela mine (MEL), pentaerythritol (PER) and the single factor variable experiment of expanded graphite (EG) were carried out. TG-DTG, DSC and FT-IR were used to analyze and study the thermal stability of fire retardant coating and the composition of the carbon layer after combustion, and the optimized fire retardant coating formula was obtained. The results show that the waterborne epoxy resin (m(E51)∶m(E20)=3∶2) was used as the film for ming material, when the additive amounts of intumescent flame retardant and expanded graphite were 26% (APP), 12%(MEL), 10%(PER) and 4%(EG), respectively, the ultimate refractory time of the coating reached 31.7 min, the expansion rate was 11.7, and the expanded carbon layer was complete and dense. The temperature corresponding to the maximum decomposition rate of fire retardant coating is 331.4 ℃, the intumescent flame retardant in 200-350 ℃ to complete the decomposition, 800 ℃ residual carbon content is 49.9%, mainly composed of polyaromatic rings, phosphate organic compounds and titanium pyrophosphate inorganic compounds. The addition of titanium dioxide, magnesium hydroxide and mineral fiber can effectively improve the fire resistance and the strength of the expanded carbon layer.
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  In-situ formation of B₄C@TiB₂ powder and its dielectric and electromagnetic absorbing properties

  ZOU Xin, CHEN Pingan, ZHU Yingli, LI Xiangcheng

  Jorunal of Functional Materials. 2023, 54(7): 7200-7206. https://doi.org/10.3969/j.issn.1001-9731.2023.07.027

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  The B₄C@TiB₂ composite powders with core-shell structure were fabricated by in-situ formation of TiB₂ on the surface of B₄C by chemical coating combined with heat treatment, which the tetrabutyl titanate and B₄C powders were used as raw materials. The results showed that the B₄C-TiB₂ core-shell interface was constructed, which transformed boron carbide from stoichiometric B₄C to boron-rich phase B₁₃C₂ and caused severe lattice distortion. When the TiB₂ content increased from 0 wt % to 20 wt %, the minimum reflection loss value (RL_min) of B₄C@TiB₂ composite powder increased from -9.76 dB to -19.94 dB. It can be attributed to the improvement of impedance matching of B₄C powders. Furthermore, the lattice distortion and core-shell structure enhanced the dipole polarization and the interface polarization, respectively. The synergistic effects improved the dielectric loss capability, which significantly improved the electromagnetic wave absorption performance of B₄C powders.
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  Preparation and properties of MCA@ADP synergistic intumescent flame retardant thermoplastic polyurethane

  RAN Yining, OU Hongxiang, WEN Kaiyue, TU Zhe, PAN Mengli, XUE Honglai

  Jorunal of Functional Materials. 2023, 54(7): 7207-7214. https://doi.org/10.3969/j.issn.1001-9731.2023.07.028

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  Thermoplastic polyurethane (TPU) is easily ignited. To improve the thermal stability of TPU and inhibit the generation of phosphine gas (PH3) at high temperature of traditional phosphorus flame retardant diethyl aluminum hypophosphite (ADP), the melamine urate (MCA) coated aluminum diethylphosphinate flame retardant (MCA@ADP) was prepared by molecular self-assembly technology. The intumescent flame retardant TPU composites were prepared by melt blending with MCA@ADP and dipentaerythritol (DPER) in different proportions. The properties of flame retardant TPU composites were studied by oxygen index, vertical combustion, thermogravimetric analysis, cone calorimeter, and mechanical properties test. The results show that when the total amount of flame retardant was 25 wt% and the mass ratio of MCA@ADP to DPER was 1∶1, the limiting oxygen index (LOI) of the flame retardant composite TPU-3 reached 34.5%, and the vertical combustion test reached UL-94 V0 level. Compared with pure TPU, the peak heat release rate (pHRR) and total heat release rate (THR) of TPU-3 decreased by 76.91% and 58.19%, respectively, and the tensile strength decreased by 38.5%. The results indicate that the nitrogen-phosphorus synergistic intumescent flame retardant system composed by MCA@ADP and DPER can effectively improve the flame retardancy of TPU composites.
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  Preparation and properties of carbon fiber reinforced SiC ceramic composites

  CAI Kang, LI Enying, SUN Guanhua, XIE Xiangyu

  Jorunal of Functional Materials. 2023, 54(7): 7215-7220. https://doi.org/10.3969/j.issn.1001-9731.2023.07.029

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  Carbon fiber reinforced SiC ceramic composites were prepared by precursor immersion pyrolysis(PIP) method with carbon fibers with different doping amounts (0,3wt%,6wt% and 9wt%) as reinforcements.The lattice structure,micro morphology and mechanical properties of the composites were studied by XRD,SEM,density,porosity and mechanical properties.The results show that carbon fiber can be well combined with SiC ceramic matrix,and the main phase of SiC is not changed.The crystallinity and density of the composites can be improved by adding an appropriate amount of carbon fiber.After adding carbon fiber,the particles of the composite become relatively closer and have obvious volume shrinkage,and when the doping content of carbon fiber is 6wt%,the cracks on the surface of the sample are the least and the morphology is the best.With the increase of carbon fiber content,the density,flexural strength and fracture toughness of composite samples increased first and then decreased,while the porosity decreased first and then increased.When the carbon fiber doping content is 6wt%,the density,flexural strength and fracture toughness of the samples reach the maximum,which are 2.91 g/cm³,233.7 MPa and 3.48 MPa.m^1/2 respectively,while the porosity reaches the minimum,which is 62.18%.It can be seen that when the carbon fiber doping content is 6wt%,the comprehensive properties of carbon fiber reinforced SiC ceramic composites are the best.
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  Boron nitride ceramics with high interfacial thermal conductivity based on direct ink writing

  XIAO Bing, REN Yan, ZHENG Xinmei, ZHAO Yang, DU Yuheng, HAN Rui, ZHAO Bike, CHEN Gang, HUANG Bingxue, LI Guangzhao, PENG Biyou

  Jorunal of Functional Materials. 2023, 54(7): 7221-7229. https://doi.org/10.3969/j.issn.1001-9731.2023.07.030

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  Boron nitride (BN) ceramics have excellent properties such as high aspect ratio, high temperature resistance, high thermal conductivity and electrical insulation, widely used in electronic information, aerospace, metallurgy, machinery and other fields. 3D printing technology has low cost and time-saving compared with traditional processing methods, and is an important molding technology for the preparation of ceramic parts with complex three-dimensional structure. To this end, in this paper, based on the self-developed pneumatic new direct-write 3D printing material forming platform, ceramic slurries with different BN contents were prepared using BN and polyvinyl alcohol (PVA) as raw materials and binder, and ceramic preforms with different 3D structures were designed and prepared using the layer-by-layer stacking principle. By changing the rheological properties of the slurries, the BN 2D nanosheets were realized in the printing process under the shear. By changing the rheological properties of the slurry, the orientation of BN 2D nanosheets under the action of shear force was achieved during the printing process, and ceramic materials with high interplanar thermal conductivity were obtained. The effect of BN content on the molding quality of the ceramic parts was investigated, and the structure and microscopic morphology of the printed ceramic materials were characterized by XRD and SEM. The results show that the BN/PVA 85 slurry has good shear thinning and viscoelastic properties, and the yield stress in the linear viscoelastic region reaches 240 Pa, which is suitable for direct-writing 3D printing technology. the increased horizontal orientation of BN inside the part contributes to the enhanced interfacial thermal conductivity of the ceramic material, where the interfacial thermal conductivity of the BN/PVA 85 ceramic part is about 4.3 W/(m·K).
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  Synthesis of MXene/persimmon tannin composite film and its supercapacitor performance

  FAN Fan, WANG Zhongmin, GAN Weijiang, LIN Zhenkun

  Jorunal of Functional Materials. 2023, 54(7): 7230-7236. https://doi.org/10.3969/j.issn.1001-9731.2023.07.031

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  Transition metal-carbon/nitride (MXene) is a two-dimensional nano-layered material with high electrochemical activity, high conductivity, high bulk density and excellent mechanical flexibility, which makes it widely used in the field of supercapacitors. However, Mxene is prone to self-stacking, which affects its performance as an electrode material. In this paper, persimmon tannin (PT) was doped into Ti₃C₂T_x Mxene through solvent heat treatment, suction filtration and other steps to prepare Ti₃C₂T_x/PT composite film material, and its morphology, structure and electrochemical performance were characterized in detail, which proved that a little PT doping can effectively improve the stacking property of Ti₃C₂T_x, make electrolyte ions diffuse rapidly, and is conducive to the improvement of composite film capacitance. However, the excessive introduction of PT will reduce the capacitance performance. The electrochemical test results show that when the current density is 1 A/g, the mass-specific capacitance of the Ti₃C₂T_x/PT_0.01 composite film electrode reaches 448 F/g, which is 23.8% higher than that of the undoped Ti₃C₂T_x film and shows better rate capability. The PT doping strategy proposed in this paper is proven as an effective means to improve the performance of Ti₃C₂T_x MXene capacitors. This strategy is expected to be further extended to other similar two-dimensional nanomaterials in the future.