Synthesis And Properties Of Composite Oxide Electrocatalysts For Hydrogen Production By Clean Electrochemical Water Splitting

The widespread use of fossil fuels emits a large amount of CO2 and air pollutants,causing serious environmental problems.The use of hydrogen energy can solve the environmental pollution problems caused by fossil fuels from the source.At present,hydrogen is mainly obtained through petrochemical processes such as water gas reaction,and still brings environmental problems such as CO2 emissions.The use of clean renewable electric power to produce hydrogen does not lead to carbon emissions,and is an ideal way to produce hydrogen in an environmentally friendly environment in the future.The oxygen evolution reaction(OER)is the anode half reaction of electrolyzed water,and its kinetic process is slow,which is the key to limiting the hydrogen production from electrolyzed water.To date,noble metal based catalysts such as RuO2 and IrO2 have been considered to be the most effective OER catalysts.However,due to the high cost and scarcity of precious metal based catalysts,they are not suitable for large scale applications.In order to solve this problem,this thesis is devoted to the study of high-performance,low-cost non-precious metal OER electrocatalysts,and further improve the electrochemical activity and stability of the catalyst by means of morphological and doping metals,and it is expected to promote electrolyzed water.The development of technology,which drives the application of hydrogen energy,feels the environmental pollution caused by fossil fuels from the source.Firstly,we use Co2(CO)8 and Fe(CO)5 as ion sources,we use oleylamine as the surfactant,and 1-octadecene is used as the solvent.CoFe nanoparticles are directly synthesized by pyrolysis.Moreover,they are supported on carbon and then annealed in air.CoFe composite oxides were obtained as a high performance oxygen evolution reaction(OER)catalyst.The OER activity of CoFe composite oxides was better than other monoacidic oxides.Then,we incorporated the W element to the CoFe binary catalyst to synthesize an amorphous CoFeW ternary metal oxide catalyst supported on carbon,which exhibits high activity for oxygen evolution reaction.After a series of regulation,a low overpotential of 300 mV is required to achieve the OER current density of 10 mA cm-2 by the CoFeWOx/C with optimized composition.The high activity is attributed to the fine-tuned electronic structure by the mixed oxides.This catalyst is also stable indicating by almost no decay after 12 h chronopotentiometric test or 1000 cyclic voltammetry.The ternary metal oxide catalyst is expected to be used in hydrogen production by electrolysis of water,which may promote the use of clean hydrogen energy and solve environmental pollution and energy shortages problems.