Construction of high-loading WO3-x sub-nanometer clusters via orderly-anchored top–down strategy boost acidic hydrogen evolution

Exploring a simple, rapid, and scalable synthesis method for the synthesis of high loading nonprecious metal sub-nanometer clusters (SNCs) electrocatalysts is one of the most promising endeavors today. Herein, an orderly-anchored top–down strategy is proposed for fabricating a new type of high loading WO_3-x SNCs on O-functional group-modified Ketjen black (WO_3-x-C(O)) to balance the high loading (49.29 wt.%) and sub-nanometer size. By optimizing the vacancy number, WO_2.71-C(O) has extremely large electrochemically active surface area (402 m² g⁻¹) and high turnover frequency value of 1.722 s⁻¹ at −50 mV (vs. reversible hydrogen electrode). The overpotential of WO_2.71-C(O) reaches 22 mV at a current density of 10 mA cm⁻², which is significantly better than the commercial Pt/C level (32 mV), achieving a breakthrough in the hydrogen evolution reaction (HER) catalytic activity of nonprecious metals in acidic environment. Theoretical calculations and in situ characterization show that this material allows for the enrichment of reactants (H*) and the optimization of intermediate adsorption, which leads to the enhancement of acidic HER catalytic activity.