Breaking the activity-stability trade-off of Au catalysts by depth-controlled TiO2 nanotraps

Abstract

The sintering of nanoparticles has always been a great challenge for supported Au catalysts. Herein, we fabricate a depth-controlled TiO2 nanotrap via area-selective atomic layer deposition (ALD) method to balance the activity and anti-sintering properties of Au nanoparticles. Au nanoparticles anchored by a 2.31 nm deep TiO2 nanotrap prepared by 25 ALD cycles of TiO2 exhibit the best overall activity for CO oxidation, where the depth of TiO2 nanotrap is close to the geometric radius of Au nanoparticle. It exhibits enhanced sintering resistance while retaining an activity similar to that of pure Au catalyst. The average size of sintered Au (8.4 ± 2.7 nm) is three times smaller than that of pure Au catalyst (21.1 ± 7.1 nm) after calcination in air at 700 °C. The performance of TiO2 nanotrapped Au catalyst breaks the conventional trade-off between the activity and anti-sintering capability of Au by exposing active sites, and hindering Au migration-coalescence simultaneously, which serves as a promising strategy to design highly stable Au catalysts.