Pd-Tipped Au Nanorods for Plasmon-Enhanced Electrocatalytic Hydrogen Evolution with Photoelectric and Photothermal Effects

Graphical Tip of the iceberg : Pd-tipped Au nanorods (NRs) are prepared in the presence of CTAB and 5-BrSA for the electrocatalytic hydrogen evolution reaction in the visible and near-infrared region. The tipped NRs exhibit a lower onset overpotential (40 mV) and higher exchange current density (1.585 mA/cm 2 ) than fully covered ones, which is ascribed to synergetic photothermal and photoelectric effects. Plasmonic bimetallic structures have been wildly used in photocatalysis, owing to their tunable optical properties and desirable catalytic activities. However, it is still a challenge to realize the enhanced electrocatalytic hydrogen evolution reaction (HER) using these structures with electric, photo-, and thermal effects. Herein, we report that Pd-tipped Au nanorods (NRs) were prepared for electrochemical water splitting in the visible and near-infrared region. The NRs exhibited a lower onset overpotential (40 mV) and high exchange current density (1.585 mA/cm 2 ), which was largely ascribed to the increased carrier density in Pd induced by photo-excited Au NRs, and further enhancement of Pd catalytic activity resulted from the photothermal effect of Au NRs. As the hot electron transport channel was hindered by excess Pd nanoparticles, it was found that the HER performance of tipped NRs was much higher than that of fully covered ones. This study extends enhanced electrocatalytic HER activity with plasmonic bimetallic structures by taking full advantage of the synergy between photoelectric and photothermal effects.