Three-in-one tandem catalysis for alkaline hydrogen evolution reaction on Pt/CoV-LDHs

Constructing a local acid-like microenvironment is an important and challenging issue for alkaline hydrogen evolution reaction (HER). In this work, we demonstrate a Three-in-one tandem catalysis strategy to achieve this goal. The ideal tandem catalyst should possess three separated active sites to drive three subsequent reaction steps, including water decomposition to construct a local acid-like microenvironment, H3O+ migration, and H2 production under alkaline conditions, respectively. Taking the Pt single atom anchored on CoV layered double hydroxides (Pt/CoV-LDHs) as a prototypical example, we have successfully constructed a local acid-like microenvironment and realized remarkable alkaline HER performances using theoretical prediction and experimental verification. In situ Raman spectroscopy observes the emergence of a key H3O+ intermediate. The further analysis reveals the mechanism of tandem catalysis that water molecule adsorbs on V site with the assistance of oxygen vacancy in CoV-LDHs; V and Co sites play synergistic role in dissociating water to construct a local acid-like microenvironment; Co sites transport H3O+ intermediate to Pt site for HER which undergoes Volmer-Tafel mechanism with fast kinetics. This work exhibits a rational on-demand design strategy of catalysis and may broaden the horizon of catalyst design.