Polyoxometalate‐Derived Ultrasmall Pt2W/WO3 Heterostructure Outperforms Platinum for Large‐Current‐Density H2 Evolution

Abstract Platinum (Pt)‐based catalysts with high Pt utilization efficiency for efficient H 2 evolution are attracting extensive attention to meet the issues of energy exhaustion and environmental pollution. Herein, a one‐step electrochemical method is demonstrated to construct ultrafine heterostructure Pt 2 W/WO 3 on reduced graphene oxide (RGO) by injecting multielectrons into the Preyssler anion NaP 5 W 30 O 110 14− to codeposit with anodic deliquescent Pt cations. The resulting Pt 2 W/WO 3 /RGO shows much higher performance than that of commercial Pt catalysts for large‐current‐density H 2 evolution, which can deliver a large current density of 500 mA cm −2 with an overpotential of only 394 mV, much lower than that of 20% Pt/C (578 mV). Comparisons with control experiments and density functional theory (DFT) calculations both suggest that the much enhanced activity can be mainly attributed to the synergistic cooperation of different components to drive fast and continuous hydrogen desorption on Pt 2 W/WO 3 /RGO, while it could not run normally for 20% Pt/C under similar conditions due to the formation of huge bubbles on the electrode surface. The effective integration of high catalytic activity and hydrogen desorption ability into a single material can yield advanced materials for large‐current‐density H 2 evolution with remarkable stability.