Photoelectrocatalytic hydrogen evolution reaction (HER) combines green photons and electrons for water splitting, but current approaches face poor catalytic performance due to high water dissociation barriers and random water-catalyst interactions, particularly in alkaline conditions. Here, we boost alkaline HER by introducing a multi-functional photoelectrocatalyst based on plasmonic-active, platinum-coated Ag nanocube (AgNC@Pt). This design leverages bimetallic hybridization to enhance catalytic activity and utilizes plasmons to manipulate interfacial water molecules for facilitating HER. Under light irradiation, AgNC@Pt reduces overpotential from 0.112 V to 0.094 V vs. RHE, corresponding to a 1.2-fold improvement and the Tafel slope value reduces from 92 mV dec−1 to 85 mV dec−1, indicating a 1.1-fold enhancement in HER kinetics. It also outperforms the gold standard Pt/C at overpotentials beyond −0.22 V, achieving a superior current density of −0.091 A cm−2 (-0.45 V vs. RHE) and reducing overpotential by 15 % at 70 mA cm−2. Our catalyst exhibits overpotential and Tafel slope that are > 8-fold (0.094 V for AgNC@Pt and 0.755 V for emerging platform) and 1.2-fold better, respectively, than emerging designs in alkaline environments. Mechanistic studies reveal that the electron-rich Pt surface and plasmonic effects are crucial for aligning water molecules on the catalyst, thereby facilitating electron transfer and proton discharge to kinetically enhance HER. By harnessing both chemical and plasmonic effects to modulate water microenvironment at the point-of-catalysis, our design offers valuable insights for achieving efficient H2 generation in practical neutral/alkaline conditions.
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Funding Info:
This research / project is supported by the Agency for Science, Technology and Research - Manufacturing, Trade, and Connectivity Individual Research Grant
Grant Reference no. : MTC IRG M23M6c0098
This research / project is supported by the Ministry of Education, Singapore - Academic Research Fund Tier 1
Grant Reference no. : RG92/24
This research / project is supported by the Nanyang Technological University - Start-up Grants
Grant Reference no. : Start-up Grants