| As an efficient method of hydrogen production,electrolyzed water has always attracted the attention of researchers.Electrolyzed water includes two parts:oxygen evolution reaction（OER）and hydrogen evolution reaction（HER）.The complex reaction process of oxygen precipitation requires a higher overpotential and consumes more energy.This is also the main problem faced by improving the efficiency of hydrogen production by electrolysis of water.Among them,the energy efficiency of the electrocatalyst is extremely critical for the reaction process.At present,most of the commonly used catalysts are precious metals and their oxides.Although they have been commercialized,most of the commonly used precious metal catalysts are very expensive,but their energy efficiency is not ideal.These obvious shortcomings make their commercial applications seriously affected and limited.Therefore,the development of resource-rich and inexpensive non-precious metal catalysts into new highly efficient and stable non-precious metal catalysts is of great significance for improving the energy efficiency of electrolyzed water,and it is also the biggest challenge for researchers at the present stage.However,the performance of non-precious metal catalysts is not good enough.How to treat non-precious metal materials through heteroatom doping and surface modification treatment to achieve ideal catalytic performance has become a research hotspot in the field of electrocatalysis at this stage.Among them,carbon fiber can be used as an ideal catalyst candidate material due to its low price,good electrical conductivity,and good physical and chemical stability.The carbon fiber can be modified by heteroatom doping to improve its catalytic performance for oxygen evolution and analyze its mechanism.Therefore,carbon materials have become a hot spot in the research hotspot of catalytic materials.In addition,metal-organic framework materials（MOFs）have become a new and popular electrocatalytic material due to their high specific surface area,adjustable porosity and easy functionalization.Catalysts derived from MOFs can be well inherited.With the above characteristics,the finally obtained electrocatalyst also has good catalytic performance.The main content of this thesis is to modify non-precious metal materials through heteroatom doping,use carbon fiber and nickel mesh as a three-dimensional substrate to make electrocatalytic electrodes,improve their catalytic performance,and explore the mechanism in depth.It mainly describes that phosphorus doping improves the catalytic performance of carbon fiber for oxygen evolution.A three-dimensional nickel-iron alloy mesh substrate is used to synthesize MOFs on the surface.During the reaction process,Fe doping on the surface MOFs improves its catalytic performance.These works provide new ideas for the preparation of catalytic electrodes with excellent performance and good stability,and also bring greater hope for the industrial production of electrolyzed water catalysts.The main work content is as follows:（1）In the work of phosphorus-doped carbon fiber,a new phosphorus doping process is used to phosphatize the carbon fiber,and phosphorus doping is realized in an efficient and convenient way.In the existing research,the phosphorus source used in phosphating is mostly phosphate,and this traditional phosphating method is not suitable for carbon fiber.The carbon fiber itself has a stable structure and high temperature resistance,and the traditional process cannot realize the phosphorus doping treatment of the carbon fiber.In the research of this thesis,a new vacuum tube sealing process is adopted,phosphorus trichloride is selected as the phosphorus source,and the carbon fiber is phosphatized in a vacuum-sealed quartz tube to obtain a highly efficient and stable phosphated carbon fiber catalytic electrode（P-CFC）.);Use XRD,SEM,XPS and other characterization methods to study the effect of phosphorus doping on the structure and catalytic performance of carbon fiber materials;by optimizing the amount of phosphorus trichloride used and the heating temperature,the final phosphating carbon fiber catalytic electrode is At a current density of 10 m A cm-2,the oxygen evolution overpotential is only 310 m V,and the stability is up to 50 hours;the results show that the phosphorus-doped carbon fiber catalytic electrode has excellent oxygen evolution catalytic performance and stability.（2）In the work of the nickel mesh-based MOFs catalytic electrode,by changing the three-dimensional substrate material,the MOFs material on the substrate surface is doped with Fe.In the research on the oxygen evolution performance of MOFs materials,most of the previous studies have improved the catalytic performance of MOFs electrodes by changing the metal ions and increasing the types of metal ions.In this paper,we choose to change the substrate and use the method of doping the metal in the substrate into the MOFs material to achieve the improvement of its electrocatalytic performance.Although the synthesis method is still hydrothermal,it is more convenient to use the substrate to achieve atomic doping.The final composite catalytic electrode based on the three-dimensional substrate needs only 285 m V for oxygen evolution at a current density of 500 m A cm-2.The stability is up to 90 hours,which enhances the stability while effectively improving the catalytic performance of oxygen evolution.The above work on the phosphorus doping treatment of carbon fiber and the modification of MOFs materials has successfully improved the oxygen evolution catalytic performance of the electrode;a new idea for improving the catalytic performance of carbon fibers and MOFs is provided for non-precious metal catalysis based on three-dimensional substrates.The commercialization of electrodes proposes a new method.The good results obtained in this work indicate that it is of great significance to the research of catalytic electrodes for water electrolysis. |
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