Controllable Synthesis Of Non-noble Transition Metal Carbide Nanomaterials Electrocatalysts And Their Catalytic Properties For Hydrogen Evolution Reaction

The two major issues of energy crisis and environmental pollution have promoted the development of clean energy conversion technology.Among various new energy sources,hydrogen energy is considered to be green and clean energy due to its high energy density,good combustion performance and environmental friendliness.Hydrogen production from electrolyzed water is considered to be one of the most promising production methods for large-scale hydrogen production.However,the economic problems caused by the use of precious metal catalysts limit the practical application of electrolyzed hydrogen production.High-efficiency electrocatalysts can effectively reduce the over-electromotive force of the hydrogen evolution reaction and accelerate the reaction kinetics.Therefore,the development of high-efficiency and low-cost electrocatalysts is the key to achieving large-scale application of electrolyzed water.Transition metal carbides such as molybdenum carbide,tungsten carbide,etc.,because of their rich sources,low cost,good thermal stability,excellent acid-base stability,platinum-like surface electronic structure and catalytic performance,have attracted the interest of researchers It has gradually become one of the most promising materials for hydrogen production from electrolyzed water.Based on this,this paper focuses on the application of cobalt,molybdenum,tungsten and other transition metal carbides with good application prospects in the electrocatalytic hydrogen evolution reaction,and has made some progress.The main contents are as follows:1. The self-supporting Co/Mo₂C-CNF electrocatalyst is obtained by carbonizing precursor fibers prepared by electrospinning that contain high molecular polymers,molybdenum sources,and cobalt sources Carbon nanofibers can not only effectively disperse and fix Co and Mo₂C nanoparticles,prevent agglomeration,but also facilitate the rapid transfer of electrons.Coupled with the synergistic effect of Co and Mo₂C,they can not only catalyze hydrogen evolution reaction in alkaline solution,but also acid and neutral solution also show excellent catalytic activity and stability.When the current density is 10 m A/cm²,the overpotential of the material in alkaline,neutral,and acid solutions is 128 m V,206 m V,and 217 m V respectively,and continuous test in alkaline and acidic solutions for 40 h without significant performance degradation,showing good catalytic activity and cycle stability.2. The solution containing ammonium phosphomolybdate hydrate,tungsten chloride and polyacrylonitrile is made into a cross-linked precursor fiber by electrospinning After pre-oxidizing and stabilizing the structure,carbonize under Ar/NH₃ mixed gas atmosphere.The bimetallic carbide Mo₂C@W₂C@C is obtained.By changing the experimental conditions such as metal salt content,calcination temperature,calcination atmosphere and holding time,the morphology can be controlled and adjusted.The material is used to test the catalytic activity of hydrogen evolution reaction in alkaline solution.When current density is 10 m A/cm²,the overpotential is 186 m V,showing good catalytic performance.Co/Mo₂C-CNF and Mo₂C@W₂C@C catalysts are synthesized via a simple electrospinning technology with a subsequent carbonization process.By combining Mo₂C with other transition metals and conductive carbon fibers,the catalytic performance of Mo₂C's hydrogen evolution reaction is significantly improved.The obtained self-supporting Co/Mo₂C-CNF materials can be directly used as electrode materials,and have good catalytic performance and stability in the whole p H range;the investigation of the reaction conditions of Mo₂C@W₂C@C materials provides a reference for the preparation of the same type of catalyst;The method can be further expanded to preparation other kinds of electrocatalysts.