Synthesis And Properties Of Metal Nanometer Catalytic Electrode Materials

With the development of society and the rapid growth of population,the consumption of traditional fossil fuels（coal,oil,natural gas,etc.）increases sharply.On the one hand,it created the risk of energy shortages.On the other hand,the use of large amounts of fossil energy also brought the risk of environmental pollution.In order to solve the problem of energy shortage and environmental pollution,the research of electrocatalytic hydrogen production（HER）,photocatalytic degradation of dyes,photocatalytic degradation（PEC）and other technologies has been widely concerned by scientists.Noble metals such as Pt、Au and Ag are the most widely used catalysts at present.However,the development and application of these catalysts are limited by the characteristics of toxicity,high cost and scarcity of raw materials.In recent years,transition metals such as Ni,Co,Ti,Fe and Zn had attracted the attention of researchers and practitioners,showing excellent performance in the field of catalysis.they are expected to become substitutes for noble metals.Therefore,this paper explored the application of non-noble metals in the field of catalysis from the perspectives of electrocatalysis,photocatalysis and photoelectrocatalysis.The main research contents and results are as follows:（1）Preparation of N,P co-doped carbon-based catalysts supported by transition metal phosphides for electrocatalytic hydrogen evolution.In this study,the heat treatment process parameters of N,P doped carbon nanofiber precursors are controlled.Ni₂P,Co₂P and Ni Co P particles were embedded into N,P doped carbon nanofibers（NPNFs）to prepare Ni Co P/NPNFs,Ni₂P/NPNFs,Co₂P/NPNFs,and their HER activity was tested.Ni Co P/NPNFs exhibited better performance compared with Ni₂P/NPNFs and Co₂P/NPNF samples in acidic conditions.In the case of a molar ratio Ni:Co:P of 1:1:1,Ni Co P/NPNFs revealed the best HER performance.Ni Co P/NPNFs exhibited overpotentials of 183 and280 mV at current densities of 1 mA cm^-2 and 10 mA cm^-2,respectively,with a Tafel slope of 94.5 mV dec^-1.（2）Preparation of TiO₂ and g-C₃N₄ composite catalyst（TiO₂/g-C₃N₄）for adsorption and photocatalytic degradation of methylene blue（MB）.Commercial TiO₂,which after hydrothermal and acid cleaning process,was compounded with urea at 550℃.g-C₃N₄generated from the decomposition of urea grows on the TiO₂.Adsorption experiments showed that the maximum adsorption capacity of TiO₂/g-C₃N₄（1:10）was 1667 mg/g.Combined with the photodegradation process,99%MB removal rate was achieved.Brunner-Emmet-Teller（BET）measurements and Fourier transform infrared spectroscopy（FTIR）results provided a basis for the study of the adsorption mechanism of TiO₂/g-C₃N₄.Meanwhile,The trapping experiment of sacrificial agent also provided a basis for the exploration of degradation mechanism.The results show that COO^-plays an important role in the adsorption process and﹒OH^-plays a major role in the photodegradation process.（3）TiO₂/ZnFe catalyst was prepared and applied to photoelectric catalysis.The TiO₂ array was grown on FTO by one-step hydrothermal method,and then non-precious metals were deposited by electrodeposition method to enhance the photoelectric performance of TiO₂.By scanning electron microscopy,it can be seen that TiO₂ array uniformly grows on the FTO.Combined with the energy spectrum,it can be seen that Zn and Fe are successfully deposited on TiO₂.The photochemical properties show that although the deposition of Zn can obtain a greater photocurrent response,it is not stable.However,the deposition of ZnFe not only increases the photocurrent of TiO₂,but also makes the photocurrent response more stable.At the same time,TiO₂/ZnFe photodegradation of MB solution can achieve 94%removal rate in 70 minutes.