Dual Active Site Engineering in Porous NiW Bimetallic Alloys for Enhanced Alkaline Hydrogen Evolution Reaction

Abstract

Utilizing dual active sites in electrocatalysts creates a synergistic effect, enabling the independent optimization of H₂O dissociation and intermediate adsorption/desorption, which in turn enhances the efficiency of the hydrogen evolution reaction (HER). Herein, a porous NiW bimetallic alloy electrocatalyst using a dynamic H₂ bubble template (DHBT) strategy is fabricated. This electrocatalyst capitalizes on the synergistic effect of dual active sites, achieving industrial-level current densities of 500 and 1000 mA cm^-2 for HER in 1.0 M KOH, with low overpotentials of 198 and 264 mV, respectively. It also demonstrates excellent stability over a 200 h test. Theoretical studies reveal that alloying Ni with W shifts the d-band center (ε_d) of the W 5d orbital downward, which enhances *OH intermediate desorption and promotes H₂O adsorption and dissociation at the W site, leading to increased active site availability. Meanwhile, this shift provides more accessible H* intermediates, further enhancing H₂ production at the Ni₂W₁ hollow site. When the porous NiW bimetallic alloy electrocatalyst is implemented in a solar-driven water splitting system, it achieves a high solar-to-hydrogen (STH) conversion efficiency of 16.59%. This work underscores the effectiveness of dual active site electrocatalysts for sustainable H₂ production.