Electrocatalytic CO₂ Reduction Performance On CuAu Alloy

The increasing concentration of CO₂ in the atmosphere has in recent years caused a lot of environmental issues.The reduction of CO₂ to hydrocarbons can help in solving environmental problems and saving the use of fossil fuels,by turning waste into treasure.Electrochemical reduction of CO₂ can be used to directly convert CO₂ to hydrocarbons.In this process,it is extremely important to look for an ideal catalyst.Amongst of all metals examined,Cu electrode,experimentally is the only metal that is able to reduce CO₂ to multi-carbon products(C₂₊)at reasonable currents and efficiencies.However,high overpotentials and a wide range of reduction products on Cu catalysts remain a significant barrier to its application.In order to overcome these shortcomings,many research groups have previously studied Cu-based bimetallic with the hope to tune catalytic properties of Cu by addition of a second metal in form of mixed alloy and core-shell structures.Bimetallic catalysts have unique properties from the hybridization of the atomic orbitals,which can shift the d-band center.In this thesis,the CuAu alloy was modified to improve the catalytic performance of the catalyst and enhance the stability and selectivity of the Cu-based catalyst.The main contents of this thesis are divided into the following aspects:?1?Nanoporous Cu?NPC?precursor were synthesized by free corrosion dealloying of Al-Cu alloy.In the process of preparing NPC,the main experimental conditions,such as the alloy composition,the corrosion temperature and the dealloying time are investigated.?2?Nanoporous AuCu alloy was fabricated by a facile in situ hydrometallurgical approach.The surface of the catalyst is mainly composed of Au₃Cu,and the interior is mainly made of NPC.AuCu alloy can significantly improve the catalytic performance.Among them,the sample of Au and Cu atoms interphase distribution is most obvious in the improvement of catalytic performance.CO faradaic efficiency is⁹5%at-0.7 V vs RHE.After 10 hours of continuous reaction,the catalytic activity was not significantly decreased.?3?CO and H₂ gas also known as syngas,are important chemical precursors that can be converted into larger hydrocarbons or small molecules.Different synthesis gas components can prepare different industrial products.So,we pursued the rational design of a series of electrocatalysts that can be used to synthesize different H₂/CO ratios.As a result,we synthesize a range of syngas compositions,the ratio of H₂/CO can be adjustable in range of 0.2-2,which is a very large adjustable range.