| At present,problems such as energy shortages and the greenhouse effect are becoming more and more serious,and carbon emission reduction should receive more attention.CO2 conversion technology has received widespread attention as a means of high-efficiency carbon emission reduction and resource utilization.The electrocatalytic carbon dioxide reduction(CO2RR)technology,as a new technology with mild reaction conditions that can be combined with clean energy,has practical development prospects.With the deepening of CO2RR research,copper-based catalysts,as the only known metal catalysts that can reduce carbon dioxide to multi-carbon products,have received more attention.However,they still face problems such as poor selectivity and serious side reactions.Therefore,it is still a challenge to design a copper-based catalyst with high selectivity,high activity and high stability.In response to the above problems,this article has conducted the following investigation and discussion.1.Designed and synthesized copper nanoparticles with rich twin boundaries on the surface,which show good activity and high selectivity to multi-carbon products such as ethylene and ethanol when used as a CO2RR catalyst,as well as good stability.Using basic copper sulfate as the precursor,the copper hydroxide/basic copper sulfate composite material was obtained by adjusting the addition amount of sodium hydroxide.With the existence of a large number of crystal regions in the composite material itself,the material is transformed into a copper nanostructure with a large number of twin boundaries on the surface during the CO2RR process.Through a variety of testing methods and techniques,the morphology,composition,structure,catalytic performance and reaction mechanism of the product were characterized and studied in detail.Studies have confirmed that because the synthetic material has a large number of twin boundaries,the atomic energy on the crystal surface is relatively high,which facilitates the adsorption of the reaction intermediate*CO,reduces the reaction energy barrier,and promotes the selective production of C2+products by CO2RR.Among them,under the potential of-1.2 V(vs.RHE),the FE of electrocatalytic CO2 to produce multi-carbon products is as high as 81.3%,and the FE of ethylene products can reach 65%,and it has a significant inhibitory effect on the side reaction of hydrogen evolution.Through the stability test,it is found that it can keep the current stable and the FE basically has no attenuation within 7 hours.The performance of the catalyst is better than most of the current reports in the literature,and it has very important research value.2.A simple method for preparing high-efficiency CO2RR electrocatalysts is proposed.First,synthesize various basic copper salts(basic copper nitrate,basic copper carbonate,basic copper chloride),and obtain various copper hydroxide/basic copper salt composite materials by adding sodium hydroxide and controlling the addition amount.Secondly,after a variety of testing and characterization techniques,they all show a similar morphology and structure to copper hydroxide/basic copper sulfate,that is,they transform into a copper nanostructure rich in a large number of twin boundaries during the CO2RR electrolysis process.Finally,after CO2RR electrocatalytic performance evaluation,it is confirmed that they can achieve high selectivity to multi-carbon products.Copper hydroxide/basic copper nitrate at-1.3 V(vs.RHE)potential,the total FE of the multi-carbon products of CO2RR can reach 71.2%;copper hydroxide/basic copper carbonate can affect the multi-carbon CO2RR under the same conditions The total FE of the product can reach 68.4%;the total FE of the multi-carbon product of CO2RR reaches 73.6%under the potential of-1.2 V(vs.RHE)for copper hydroxide/basic copper chloride.Therefore,this paper provides a general,simple,low-cost and highly selective CO2RR electrocatalyst synthesis method,which provides a new idea for the design of high-efficiency CO2RR catalysts. |
PDF Full Text Request