Self-assembly of metal/semiconductor heterostructures via ligand engineering: unravelling the synergistic dual roles of metal nanocrystals toward plasmonic photoredox catalysis

Abstract

Metal nanocrystals (NCs) have been recognized as an important class of nanomaterials by virtue of their unique surface plasmon resonance (SPR) effect and pivotal roles as electron traps in photocatalysis. Nevertheless, it is still challenging to unambiguously unravel and simultaneously harness the dual synergistic roles of metal NCs in a single photocatalytic system for solar-to-chemical energy conversion. Herein, an efficient ligand-triggered electrostatic self-assembly strategy was developed to achieve the spontaneous and monodispersed attachment of Au NCs onto 1D WO₃ nanorods (NRs) via pronounced electrostatic attractive interaction, in which tailor-made positively charged Au NCs were closely integrated with negatively charged WO₃ NRs. The intimate integration of Au NCs with WO₃ NRs at the nanoscale could significantly benefit the extraction, separation, and migration of plasmon-induced energetic hot carriers over Au NCs and promote the separation of photogenerated charge carriers over the WO₃ substrate. Such a cooperative synergy stemming from SPR and the electron-withdrawal effects of the Au NCs resulted in distinctly enhanced photoredox catalytic performances for plasmonic photocatalysis under both simulated solar and visible light irradiation. Our study highlights the significance of utilizing a rational interface design between metal NCs and semiconductors for excavating the multifarious roles of metal NCs in substantial solar energy conversion.