Electrocatalytic CO2 reduction reaction(CO2RR)has been regarded as a highly effective strategy to produce valuable fuels and feedstocks,contributing to achieving a carbon-neutral cycle and dramatically mitigating CO2 emission[1-6].Generally,alkaline or near-neutral solution,such as KOH or KHCO3 aqueous solution,is employed as elec-trolytes for CO2RR owing to higher solubility of CO2 in electrolytes[1,7-10].However,thermodynamically more favorable reactions of CO2 with hydroxide to form car-bonate in both alkaline and neutral reactors,rather than CO2 reduction,results in large voltage and CO2 losses[2,11],which imposes a prohibitive carbon utilization efficiency.Concerning this issue,the strategy of operating CO2RR in acidic electrolytes has been paid more attention because of the advantages of reducing carbonate formation to almost zero and eliminating CO2 crossover(Fig.1a,b).Specifically,no carbonate will be generated or converted back to CO2 by protons when H3O+or H2O is the proton source,respectively[12].Nevertheless,kinetically favor-able hydrogen evolution reaction(HER)prevails over CO2RR under an acidic condition,which results in the Faraday efficiency(FE)for CO2RR near zero in strong acids with pH＜1.Very recently,Sargent et al.have developed a cation-augmenting strategy to circumvent HER and achieve outstanding electrocatalytic performance for CO2RR in strong acids via tuning the concentrations of potassium cations(K+)[2].

Tianjin Key Laboratory of Molecular Optoelectronic Sciences,Department of Chemistry,School of Science,Tianjin University&Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300072,China

[1]Jun-Jun Li;Zhi-Cheng Zhang-.K+-enhanced electrocatalytic CO2 reduction to multicarbon products in strong acid)[J].稀有金属（英文版）,2022(03):723-725

H3O+or

K+,enhanced,electrocatalytic,reduction,multicarbon,products,strong,Electrocatalytic,CO2RR,has,been,regarded,highly,effective,strategy,produce,valuable,fuels,feedstocks,contributing,achieving,neutral,cycle,dramatically,mitigating,emission,Generally,alkaline,near,solution,such,KOH,KHCO3,aqueous,employed,owing,higher,solubility,electrolytes,However,thermodynamically,more,favorable,reactions,hydroxide,both,reactors,rather,than,results,large,voltage,losses,which,imposes,prohibitive,utilization,efficiency,Concerning,this,issue,operating,acidic,paid,attention,because,advantages,reducing,carbonate,formation,almost,zero,eliminating,crossover,Fig,1a,Specifically,no,will,generated,converted,back,by,protons,when,H2O,source,respectively,Nevertheless,kinetically,hydrogen,evolution,HER,prevails,under,condition,Faraday,FE,acids,Very,recently,Sargent,have,developed,augmenting,circumvent,achieve,outstanding,performance,via,tuning,concentrations,potassium,cations

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