Preparation Of Copper/Nitrogen Doped Carbon Nanosheets Composite Materials And Its Application In Electrocatalytic Of Methyl N-phenylcarbamate

Carbon dioxide?CO₂?is the main gas that causes the greenhouse effect,and it is also an important C1 resource.The recovery and utilization of CO₂ is of great significance of the sustainable development of society.Carbamate compounds are a class of chemicals with a wide range of industrial uses.Using CO2 as a carbonyl source to participate in the synthesis of carbamate compounds is a very attractive method to achieve CO₂ fixation and resource utilization.However,the high thermodynamic stability of CO₂ itself severely limits its reactivity.Promoting the activation of CO2 by means of electrocatalysis is an effective method of the synthesis of carbamates under mild conditions.It is of great significance to further improve the efficiency of the synthesis of carbamates using electrocatalytic means,through the development of highly efficient electrocatalysts.Metal nanoparticles have much higher catalytic activity than bulk metals.Supporting metal nanoparticles on a carrier to prepare a supported nanocatalyst can greatly increase the stability of the catalyst while further improving the performance.Nitrogen-doped nano-carbon materials have the advantages of good conductivity,good stability and large surface area.At the same time,when it acts as a catalyst carrier,it can generate a strong binding effect of the coordination bond and the metal particles,which further improves the stability of the catalyst.Therefore,the nitrogen-doped nano-carbon material is a very good choice as an electrocatalyst carrier.The particle size of metal nanoparticles has a huge impact on the performance of the catalyst,so the single atom catalyst that reduces the metal particle size to the limit has received widespread attention.Because of its unique structural characteristics,single-atom catalysts have demonstrated excellent activity in a variety of electrocatalytic reactions.Based on the good performance of various supported nanocatalysts and single-atom catalysts in the electrocatalytic CO₂ reduction process,it is speculated that they may have great potential for the efficient electrocatalytic synthesis of carbamates.In this thesis,copper nanoparticles/nitrogen-doped carbon nanocomposites?Cu/N-C?and atomically dispersed copper-nitrogen-doped carbon nanosheet composites?Cu-N-C?were prepared for the electrosynthesis of methyl N-phenylcarbamate.The catalytic effect of two types of materials on the reaction process was explored,and the reaction conditions of electrolysis were optimized.The specific research content is as follows:?1?Copper nanoparticles/nitrogen-doped carbon nanocomposites?Cu/N-C?with different copper loadings were prepared by the impregnation method.The materials were characterized and their electrocatalytic properties were studied.Through research,it is found that the loading of copper has a great relationship with the dispersibility and catalytic performance of copper on the material.Among all Cu/N-C materials,Cu/N-C-2material has the best catalytic performance.The traditional copper sheet electrode was used to obtain a 22%yield under theoretical electric quantity,while the prepared Cu/N-C-2 was used as the electrode material to obtain a 35%yield.The effect of current density on the catalytic effect of Cu/N-C-2 materials was studied.After repeated use,the catalytic performance of the Cu/N-C-2 material gradually decreased,and the nano-copper particles also showed agglomeration.It shows that the material has the problem of limited stability.?2?Using a copper-containing MOF material as a precursor,an atomically dispersed copper-nitrogen-doped carbon nanosheet composite?Cu-N-C?was prepared by MOF derivation.Through characterization,it was found that the three elements of Cu,N and C were evenly distributed on the material;copper atoms scattered on the material in isolation from each other.The study also found that the amount of nitrogen source has a great influence on the copper content and nitrogen content in Cu-N-C materials.Among all the Cu-N-C materials,Cu-N-C-3 material has the best catalytic performance;using Cu-N-C-3 material as the electrode,the yield of 52%is achieved under the theoretical electric quantity.The effect of current density and electric quantity on the catalytic performance of Cu-N-C-3 materials was explored.By exploring the reuse performance of Cu-N-C-3 material,it was found that the material has good stability.