Activation of inert Ag by nanoplasmonic synergy for enhanced hydrogen evolution reaction

The application of Ag as an electrocatalyst for hydrogen evolution reaction (HER), which holds promise to quench the worldwide thirst for clean energy source, is severely limited by its poor intrinsic activity. To address this issue, in the present contribution the Ag electrode is anodically etched, giving rise to the Ag nanocorals (NCs) consisted of closely interconnected Ag nanoparticles (NPs), between which the grain boundaries are flooded with coordinately unsaturated Ag atoms. Electrokinetic studies reveal that those under–coordinated Ag atoms stabilize the hydrogen intermediates bound to Ag NCs to facilitate the subsequent transfer of the hot electrons stemmed from the relaxation of the localized surface plasmon resonance (LSPR) of Ag NCs under visible and near–infrared (NIR) light illumination. As a result of such synergistic effect is HER over Ag NCs largely accelerated, resulting in the cathodic current density of 10 mA cm⁻² readily turned on at an early overpotential η = 156 mV with respect to those of additional Ag-based electrocatalysts reported in the literature. Such outperformance unambiguously highlights the strong prospect of Ag NCs as an alternative photoelectrocatalyst, which additionally takes advantage of the incident light to boost HER, to the state–of–the–art Pt electrocatalytic counterpart for solar fuel production.