Stabilizing ultrasmall Au clusters for enhanced photoredox catalysis

Recently, loading
ligand-protected gold (Au) clusters as visible light photosensitizers onto
various supports for photoredox
catalysis has attracted considerable attention. However, the efficient control of long-term photostability of Au
clusters on the metal-support interface remains challenging. Herein, we report a simple and efficient method for
enhancing the photostability of glutathione-protected Au clusters (Au GSH
clusters) loaded on the surface of SiO2 sphere by utilizing multifunctional
branched poly-ethylenimine (BPEI) as a surface charge
modifying, reducing and stabilizing agent. The sequential coating of thickness
controlled TiO2 shells can
further significantly improve the photocatalytic
efficiency, while such structurally designed
core-shell SiO2-Au GSH clusters-BPEI@TiO2 composites
maintain high photostability during longtime light illumination conditions. This
joint strategy via interfacial
modification and composition engineering
provides a facile guideline
for stabilizing ultrasmall Au
clusters and rational design of Au clusters-based composites
with improved activity toward targeting applications in photoredox catalysis.