In situ/operando characterization techniques for electrochemical CO_(2)reduction

Utilizing CO_(2)as a carbon feedstock for producing fuels and useful chemicals is attractive due to the advantages of being abundant,nontoxic,and economical.Electrochemical CO_(2)reduction(CO_(2)RR)provides an avenue to close the anthropogenic carbon cycle.However,the reaction process of multi-electronic products of CO_(2)RR is quite complex.It is hard to yield a target product with high selectivity,high current density,low overpotential,and good stability simultaneously.In recent years,in situ/operando characterization techniques have played important roles in the catalysis field via establishing the structure-reactivity/selectivity relationships of catalysts and thereby obtaining information about mechanisms.As a result,it is necessary to apply in situ/operando characterization technologies to clarify the reaction pathway of CO_(2)RR.In this mini-review,we discuss recent progress on the in situ/operando characterizations for electrochemical CO_(2)RR,including microscopies,infrared spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy,and X-ray absorption fine spectroscopy.Moreover,the capabilities of these in situ/operando characterizations and the remaining challenges are also discussed.