Study On The Preparation And Electrochemical Properties Of Mo₂C Based Composites

In recent years,many problems such as energy exhaustion and environmental pollution have been caused by the burning of fossil fuels.Hydrogen has attracted wide research attention due to its high combustion value,fast burning rate,and environmentally friendly products without pollution.Among the many hydrogen production technologies,electrocatalytic water splitting into hydrogen production is considered as a clean and sustainable method,in which the electrocatalyst showed important function,so high-performance catalysts are being the research interest.Transition metal compounds have good electrochemical performance and stability and are regarded as ideal catalyst materials.However,most transition metal compounds are only used to study hydrogen evolution or oxygen evolution semi-reactions,and few reports have been reported on their use as bifunctional catalysts.In this paper,new catalysts are prepared based on transition metal-based Mo₂C by heteroatom doping and multiple materials composition methods.The components showed a complementary role and achieved synergy effect.The specific contents and obtained results are as follows:?1?Using PANI as the nitrogen source,the Mo₂C/PANI composite was synthesized by annealing treatment,and its structure and morphology were characterized.Molybdenum carbide becomes rough and porous after nitrogen doping,which increases the active site and improves the catalytic performance.The electrochemical test results show that in the HER test,Mo₂C/PANI has a small overpotential?-330 m V at current density 10 m V/cm²?and a small Tafel slope?100 m V/dec?.In the OER test,overpotential is 270 m V?current density 10 m A/cm²?and the Tafel slope is 99 m V/dec.In addition,Mo₂C/PANI showed the good stability.?2?Based on carbon cloth,by hydrothermal method,Zn_xNi_1-xS@Mo₂C was loaded on the surface of the carbon cloth to form an air-repellent structure,and the morphology and structure of products were characterized.The electrochemical test results show that in the HER test,Zn_xNi_1-xS@Mo₂C/CC has a small overpotential?-350 m V at current density 10 m V/cm²?and a small Tafel slope?189 m V/dec?.In the OER test,splitting potential is 1.48 V?current density10 m A/cm²?and the Tafel slope is 130 m V/dec.In addition,Zn_xNi_1-xS@Mo₂C/CC showed the good stability.?3?NiCo₂O₄@Mo₂C/PANI/CC was prepared and its structure and morphology were characterized.The electrochemical test results show that in the HER test,NiCo₂O₄@Mo₂C/PANI/CC has a small overpotential?-340 m V at current density 10 m A/cm²?and a small Tafel slope?92 m V/dec?.In the OER test,splitting potential is 1.45 V?current density 10 m A/cm²?and the Tafel slope is 88 m V/dec.In addition,NiCo₂O₄@Mo₂C/PANI/CC showed the excellent stability.?4?Mo₂C/Co Mo S₄was synthesized by hydrothermal method and its structure and morphology were characterized.The electrochemical test results show that in the HER test,Mo₂C/Co Mo S₄has a small overpotential?-316 m V at current density 10 m A/cm²?and a small Tafel slope?90 m V/dec?.In the OER test,overpotential is 250 m V?current density 10 m A/cm²?and the Tafel slope is 75 m V/dec.In addition,Mo₂C/Co Mo S₄showed the good stability.