Oxygen vacancy mediated Pd-SA/TiO2 single-atom catalyst created via ultra-fast one-step synthesis for enhanced CO2 photoreduction.

Single-atom catalysts (SACs) have garnered considerable interest in the field of heterogeneous catalysis. This study detail the synthesis of single-atom Pd catalysts supported on metal oxides using the Flame Spray Pyrolysis (FSP) method. This technique allows for the preparation of TiO₂ with abundant oxygen vacancies by incorporating a hydrogen-rich atmosphere at high temperature (>2000 K) utilizing the quenching ring, which enhances the catalyst synthesis process. Additionally, the distribution and electronic structure of Pd were tailored in a hydrogen-rich atmosphere, which promoted the entrapment of Pd atoms within oxygen vacancies, preventing their aggregation into Pd nanoparticles and leading to the formation of Pd-SA/TiO₂. Notably, Pd-SA/TiO₂ achieves 92.51 % CO₂-to-CO selectivity in the photocatalytic CO₂ reduction reaction and exhibits an impressive catalytic activity of 56.84μmol g^-1h^-1. This research introduces a novel approach to modulate the anchoring process and optimize the microenvironment for single-atom metal synthesis, advancing the development of the-state-of-the-art SACs.