Applied Catalysis B-environmental | 2021
Exerting charge transfer to stabilize Au nanoclusters for enhanced photocatalytic performance toward selective oxidation of amines
Abstract
Abstract Atomically precise gold nanoclusters have received increasing attention in photocatalysis but suffered from self-oxidation coalescence induced by photo-generated holes. Herein, we report an efficient charge engineering strategy to improve the photo-oxidation activity and stability of Au25(PPh3)10(SC3H6Si(OC2H5)3)5Cl2 nanocluster (AuNC) taking advantage of Z-scheme AuNC/ultrathin BiOCl nanosheets (2D-BiOCl) heterojunction for visible light oxidative self-coupling of amines. The turnover frequency (TOF) over AuNC/2D-BiOCl for benzylamine can reach 1916 h―1, much higher than that of most previously reported gold catalysts with a TOF usually less than 500 h―1. Moreover, the heterojunction can be stabilized for six cycles with the intact structure of AuNC remained. The enhanced photocatalytic activity of AuNC/2D-BiOCl was predominantly attributed to the formation of Z-scheme heterojunction, which effectively accelerated the transfer and separation of photo-generated carriers. Especially, the consumption of holes in AuNC by injected electrons from 2D-BiOCl can inhibit the self-oxidation of AuNC, thus improve its stability. This study provides some insights into the design of metal nanocluster catalysts with Z-scheme charge transfer for the application of photocatalysis.