Design Of Mn Single Atom And PdCu Cluster Catalysts And Their Electrocatalytic Performance For N₂/CO₂ Reduction

Ammonia（NH₃）is currently one of the most productive chemical products on the planet,and can be used as chemical raw materials,agricultural fertilizers and hydrogen-rich carriers.For a long time,Haber-Bosch method has been used to prepare ammonia,which not only caused a large amount of energy consumption,but also emitted a large amount of CO₂ gas.The electrocatalytic nitrogen reduction reaction（NRR）not only can be carried out at room temperature and under atmospheric pressure,but also can achieve green and sustainable ammonia synthesis,which has attracted wide attention from researchers.In this thesis,a catalyst with single manganese atoms supported on a porous carbon substrate was prepared by a wet chemical method.The Mn-O bonding conditions were finely controlled to construct single Mn-O₃N₁ sites anchored on the porous carbon（Mn-O₃N₁/PC）.The NH₃ yield of the catalyst reach 66.41μgh^-1 mg^-1_cat.at-0.35V（relative to reversible hydrogen）,and the corresponding Faraday efficiency is9.91%.The improvement of the NRR performance is attributed to its unique geometry and electronic structure,which not only facilitates the adsorption and activation of N₂molecules,but also reduces the free energy barrier of the potential-determining step.The extensive use of fossil fuels has brought about excessive emission of CO₂ gas,which has caused the greenhouse effect.In order to solve this problem,the fixation and conversion of CO₂ gas have become very important for achieving environmental and energy sustainability.Electrocatalytic carbon dioxide reduction is an ideal carbon cycle solution because it can reduce CO₂ to high value-added fuels and chemicals at room temperature and under atmospheric pressure.In this thesis,a catalyst with Pd Cu bi-element clusters supported on porous carbon（PdCu/PC）is synthesized by a wet chemical method.The Faraday efficiency reaches 80%,and it exhibits a good electrocatalytic stability.This work may inspire the development of efficient catalysts with multi-element synergy.