Design,Synthesis And Mechanism Of Transition Metal Electrocatalysts For Nitrogen Reduction And Water Splitting

Electrochemical water splitting and electrocatalytic nitrogen reduction（N₂reduction reaction,NRR）are two crucial technologies for energy coversion and stroge.However,the slow kinetics,high overpotential and low selectivity of electrocatalysts impede practical applications,and therefore,it is important to find a suitable and efficient catalyst.Therefore,we performed a series of work on the design,synthesis and development of this high electrocatalyst:Inspired by biological nitrogenase,we designed and synthesized Modoped FeS₂catalyst by two-step method of low temperature liquid phase reaction and solvothermal reaction.The FeS₂ substrate can inhibit the competitive hydrogen evolution reaction and the Moatom can effectively enhance the adsorption and activation ability of N₂,and the synergy between the above two can achieve high selectivity to N₂.The catalyst was found to have the best selectivity to N₂ at-0.2 V vs RHE,the Faraday efficiency of N₂ was 14.41%,and the substitution of N₂ was 26.15μg h^-1 mg^-1.We confirmed that the Moatom is the active site of the catalyst by adjusting the substitution of Moatoms and comparing the NRR properties of FeS₂ and MoS₂.2.We adopted pulsed laser laser liquid ablation method（PLAL）to prepare Ir nanospheres（Ir NSs）with abundant surface atomic steps.The prepared Ir NSs show oxygen evolution reaction and hydrogen evolution reaction activit,indicating that the the atomic step on the surface of particles is favorable for catalytic performance.Moreover,the prepared Ir NSs are applied for overall water splitting as a bifunctional catalyst,achieving extremely low battery voltage(1.535 V@10 mA cm^-2)in 0.5 M H₂SO₄,and 100 mV lower than the Pt/C and Ir/C.