Improved CdS photocatalytic H2 evolution using Au-Ag nanoparticles with tunable plasmon-enhanced resonance energy transfer.

Abstract

Plasmon-mediated photocatalytic systems often suffer from weak absorption spectra overlap which limits energy transfer between plasmon metals and semiconductors. Herein, Au-Agx@CdS90 nanoparticles (NPs) with adjustable spectral overlap were prepared. Au-Ag hollow nanoparticles (HNPs) with tunable plasmon absorption peaks were used as the template and were coated with CdS to achieve stepwise spectral overlap for enhanced energy transfer. As the spectral overlap increased between Au-Ag HNPs and CdS, the H2 evolution rate increased and then decreased. Under visible-light irradiation, Au-Ag487@CdS90 nanoparticles (NPs) delivered an H2 evolution rate of 18.73 mmol h-1 g-1, which was 2.2 times higher than pure CdS. The plasmon resonance energy transfer from Au-Ag HNPs to the CdS semiconductor increased the generation of charge carriers in the semiconductor and enhanced the photocatalytic performance. By regulating the position of the plasmon absorption peaks of the noble metal nanoparticles, changing the spectral overlap between metal and semiconductor to enhance the PRET effect is beneficial to the design of new plasmon photocatalysts.