Carbon-Encapsulated WOx Hybrids as Efficient Catalysts for Hydrogen Evolution.

Developing non-noble metal catalysts as Pt substitutes, with good activity and stability, remains a great challenge for cost-effective electrochemical evolution of hydrogen. Herein, carbon-encapsulated WOx anchored on a carbon support (WOx @C/C) that has remarkable Pt-like catalytic behavior for the hydrogen evolution reaction (HER) is reported. Theoretical calculations reveal that carbon encapsulation improves the conductivity, acting as an electron acceptor/donor, and also modifies the Gibbs free energy of H* values for different adsorption sites (carbon atoms over the W atom, O atom, WO bond, and hollow sites). Experimental results confirm that WOx @C/C obtained at 900 °C with 40 wt% metal loading has excellent HER activity regarding its Tafel slope and overpotential at 10 and 60 mA cm-2 , and also has outstanding stability at -50 mV for 18 h. Overall, the results and facile synthesis method offer an exciting avenue for the design of cost-effective catalysts for scalable hydrogen generation.