Room-temperature defect-engineered titania: An efficient platform for Pt single atom decoration for photocatalytic H2 evolution

Single-atom (SA) decoration represents the forefront of technological advancements in heterogeneous catalysis, harnessing the exceptional performance of catalysts at the atomic level. However, the high surface energy of isolated atoms often leads to agglomeration, resulting in the formation of nanoparticles. To address this challenge, trapping single atoms within surface defects has emerged as an effective strategy for atom immobilization. Conventional defect engineering techniques, such as high-temperature thermal reduction, suffer from adverse effects, such as sintering of the support material. In this study, we introduce a novel and facile room-temperature sonochemical method to induce well-defined atomic-scale defects on the surface of highly active TiO2 nanosheets, predominantly exposing the (001) facet. By introducing a highly diluted Pt precursor to the ultrasonicated nanosheet slurry, isolated Pt atoms were selectively trapped within freshly formed defects. Remarkably, the resulting Pt single atom decorated samples exhibit a striking 100-fold increase in photocatalytic H2 evolution compared to pristine TiO2 nanosheets. Notably, we demonstrate that the density of the generated defects and the loading of Pt single atoms can be precisely tailored by adjusting the sonication time. Atomic-scale characterization, complemented by density functional theory (DFT) calculations, provides compelling evidence of the strong bonding between Pt single atoms and the defects generated via sonochemical treatment. Our findings offer a promising approach for defect engineering and SA decoration on a larger scale, underscoring the significant potential of this room-temperature technique for heterogeneous catalysis.