In situ identification of active sites during electrocatalytic hydrogen evolution

The rational design of efficient,low cost,and durable catalysts is critical for the industrial applications of electrocatalytic hydrogen production.A key step towards the structure design of high-performance catalysts for hydrogen evolution reaction(HER)relies on the in situ identification of the catalytic active sites in the process of HER,which is of great challenge.In this review,we summarize the recent advances on the in situ investigation of the active sites on low dimensional catalysts for HER.We highlight the characterization techniques used for this purpose,including scanning electrochemical microscopy(SECM),scanning electrochemical cell microscopy(SECCM),electrochemical scanning tunneling microscopy(EC-STM),in situ liquid phase transmission electron microscopy(LP-TEM),and in situ spectroscopic tools.We conclude with an overview of the main technical limitations for the current approaches and give an outlook to future opportunities in this emerging field.