Visible light-enhanced synergistic catalysis of AuCu nanostructures immobilized within porous support

Abstract

In this study, 2.5 wt% of Au and Cu were uniformly immobilized within the pores of hierarchically porous zeotype materials to investigate the plasmonic catalysis under visible-light irradiation. Both monometallic and bimetallic catalysts of Au and Cu were prepared to investigate the catalytic performance due to the synergistic interaction between the two metal nanoparticles (NPs). All the prepared catalysts were characterized using PXRD, HAADF-STEM, DRS-UV and XAS to unveil the proximity and interaction between bimetallic NPs. The HAADF-STEM images revealed the proximity between Au and Cu NPs, and a significant difference in the NPs size was observed. Owing to the very small size of Cu NPs, exceptional behaviour of Cu-containing catalysts was observed. Plasmonic activity of the photocatalysts was investigated using p-nitrophenol (4-NP) reduction as a model reaction in the presence of ammonia borane as an in situ source of hydrogen. Interestingly, a 3.7-times enhancement in the rate of 4-NP reduction was achieved in the presence of bimetallic Cu/Au/HP-AlPO-5 (LSPR) under visible light irradiation compared to the dark conditions. We believe our findings will pave the way for advanced research to understand the unique plasmonic behaviour of AuCu NPs under light conditions.