EXTENDED ABSTRACT: The catalytic activity of a given catalyst can be inffuenced by a variety of intrinsic properties of catalysts; thus more than one descriptors are required to capture the catalytic activity. Based on the Arrhenius equations, the HER performance is mainly dependent on the ∆G_(H*) related activation barrier, and the proton concentration. Here, with our development of the fixed-potential method, we are able to establish the relationship between the proton concentration and PZC of the electrode under applied potential. A new HER volcano is constructed by integrating the descriptors of PZC and ∆G_(H*) without experimental data inputting. Based on the HER volcano, not only the optimal adsorption energy but also a large negative PZC in absolute potential scale are required for a catalyst with outstanding HER performance. The two descriptors volcano predict the activity trends of the pure metal in close agreement with the experimental results, enrich the design principle for HER catalyst and provide the guideline to increase the selectivity of other reduction reactions.

Keywords：Fixed-potential method; descriptors; HER volcano.

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