Plasmon-Enhanced Hydrogen Evolution on Specific Facet of Silver Nanocrystals

Hydrogen evolution reaction (HER) from electrocatalytic water splitting is a prospective technology to supply clean energy with low environmental impact for the future. In this work, plasmonic silver nanocubes (AgNCs) with (100) facet and silver nanooctahedra (AgNOs) with (111) facet were applied as the light-harvesting catalysts for enhancing hydrogen production in the plasmon-activated HER electrochemical system. As light harvesters, AgNCs and AgNOs can efficiently absorb light ranging from ultraviolet to near-infrared to generate hot electrons for facilitating electrocatalytic HER. Both AgNCs and AgNOs revealed the light-harvesting capability to improve HER activities with laser irradiation. Moreover, the current densities of AgNOs with (111) facet were higher than those of AgNCs with (100) facet for electrocatalytic HER under irradiations with three different laser wavelengths. The density functional theory (DFT) simulations revealed that the adsorption energy of the surfaces followed the order Ag(111) < Ag(100), indicating that hydrogen could be easily desorbed on the Ag(111) surface for HER. Combination of the experimental HER results and DFT simulations expressed that AgNOs with (111) facet were the excellent light harvesters in this study. Based on the DFT simulations of the H-Ag(111) and H-Ag(100) systems, the findings could be extended to other plasmon-enhanced HER electrochemical systems and could enable electrocatalysts to be designed at the atomic level.