电催化CO2还原耦合HCHO氧化反应系统促进污染物同步经济高效资源化转化OA北大核心CSTPCD

Due to rapid industrial development and human activities,CO2 emissions have led to serious environmental/ecological problems and climate changes such as global warming.Due to this situation,achieving carbon neutrality has become an urgent mission to improve the future of mankind.The use of the electrocatalytic CO2 reduction reaction(CO2RR)to produce higher-value fuels and chemicals is an effective strategy for reducing CO2 emissions and easing the energy crisis.The water oxidation half-reaction(WOR),which occurs at the anode in a traditional CO2RR system,typically suffers from slow kinetics,a large overpotential,and high energy consumption.The organic pollutant formaldehyde(HCHO)is oxidized into industrial materials(such as formic acid)under neutral conditions,which is of great significance for the sustainable production of energy and lessening environmental pollution.In addition,the number of electron transfers involved and the required potential for the HCHO oxidation half-reaction(FOR)are smaller than those of WOR,suggesting that FOR could potentially replace WOR as a coupling reaction with CO2 reduction.In this study,FOR at a MnO2/CP anode is introduced to produce a novel paired CO2RR/FOR system.The current density and generation rate of CO2RR products in this paired CO2RR/FOR system are generally larger than those of conventional CO2RR/WOR systems at the same applied potential.Moreover,in paired CO2RR/FOR systems,HCHO can be selectively converted into HCOOH at certain applied potentials.Nearly 90%of the HCHO can be selectively converted to HCOOH with a conversion efficiency of about 48%at a cell voltage of 3.5 V in a two-electrode paired CO2RR/FOR system.More significantly,under a different working current,the potentials required for FOR are systemically smaller than those for WOR.At-10 mA∙cm-2,the cell voltage of the paired CO2RR/FOR system can be reduced by 210 mV,and the required electric energy for the paired CO2RR/FOR system can be reduced by 45.13%compared with the sum of single CO2RR and FOR systems.Notably,when a commercial polysilicon solar cell is used as the power supply,improvements in the current density,the generation rate of CO2RR products,and the HCHO to HCOOH selectivity can be still achieved in the paired CO2RR/FOR system.The present work will inspire further studies for developing novel paired CO2RR systems for the cost-effective,simultaneous conversion of CO2 and organic pollutants into valuable chemicals.