Copper Oxide For Electroreduction Of Carbon Dioxide To Ethanol And N-propanol

Since the 19th century,the greenhouse effect caused by CO₂ has become more and more serious,and more and more scientists are investing in the research of fixation and utilization of CO₂.Among many CO₂ conversion and utilization methods,electrochemical reduction of CO₂ in aqueous solution don’t need to add reducing agents.The reaction conditions are mild and can be at normal temperature and pressure,so it has high safety and is environment friendly.Electrochemical reduction of CO₂ to alcohol has both environmental and energy benefits.Because it can reduce the content of CO₂ in the atmosphere on the one hand,these alcohols produced are superior energy substances on the other hand.Copper-based catalysts are common catalysts for electrochemical reduction of CO₂.Copper-based compounds can mainly electroreduction of CO₂ to hydrocarbons,and can also electroreduction of CO₂ to alcohols.But the selectivity to ethanol and n-propanol is poor,the Faraday current efficiency is low.Therefore,it is of great significance to modify the composition,structure,morphology and size of the copper-based catalyst to improve the selectivity and the Faraday current efficiency of the catalyst for the reduction of CO₂ to alcohol.The main research work in this dissertation is to calcine the intermediate to prepare CuO materials,and their applications in the electrocatalytic reduction of CO₂ to ethanol and n-propanol.The specific experimental research contents are as follows:（1）Application of CuO prepared by calcining simple intermediates in electrocatalytic reduction of CO₂Simple intermediate Cu_xO_y were selected and calcined in a muffle furnace to prepare CuO materials,which were coated on carbon paper as working electrodes.The prepared CuO materials were characterized by XRD,SEM,and electric double layer capacitance test.The effects of calcination intermediate,calcination temperature on CuO materials were investigated.Then,the CuO material prepared by the method is made into an electrode which used as a cathode,the Pt sheet is used as an anode,and0.2 M KHCO₃ aqueous solution is used as an electrolyte.In an H-type electrolytic cell,CO₂ was converted into ethanol and n-propanol by galvanostatic electrolysis under the state of CO₂ saturation.The electrode material,coating amount,electrolysis amount and current density were all examined.（2）Application of CuO prepared by calcination of Cu-MOFs in electrocatalytic reduction of CO₂Cu-MOFs have large specific surface area,adjustable structure and high porosity,so they are excellent intermediates.Choosing Cu-MOFs as calcined intermediates is beneficial to the preparation of CuO with special morphology and to improve the total current efficiency of electrocatalytic reduction of CO₂ to alcohols.Cu-MOFs materials with different ligands were prepared and characterized by FT-IR,XRD,elemental analysis,Mapping,SEM and BET.Cu-MOFs were calcined in muffle furnaces to prepare CuO materials.The prepared CuO materials were characterized by XRD,SEM and electric double layer capacitance test.The CuO material prepared by the method is made into an electrode,and the CO₂ is reduced by galvanostatic electrolysis,and the reduction products are ethanol and n-propanol.The effects of ligand,calcination temperature,current density,electrolysis amount and coating amount on the current efficiency of ethanol and n-propanol were investigated.When the current density is 6.6mA cm^-2,the electrolytic quantity is 75 C,and the coating amount is 1.11 mg cm^-2,the CuO-e3 material prepared by calcining Cu-MOF-1 at 400°C shows good catalysis for electroreduction of CO₂.The total current efficiency of alcohol is the highest,which is up to 52.2%,wherein the current efficiency of ethanol is 33.8%,and the current efficiency of n-propanol is 18.4%.