Engineering stable Pt nanoparticles and oxygen vacancies on defective TiO2 via introducing strong electronic metal-support interaction for efficient CO2 photoreduction

Abstract

This work for the first time reports the promoting effect of strong electronic metal-support interaction (EMSI) in Pt/TiO2-VO (VO: oxygen vacancy) for gas-phase CO2 photoreduction. A novel in-situ surface hydrogenation was developed to prepare hydrogenated Pt/TiO2-VO in a continuous, high throughput diffusion flame aerosol reactor. The combined results of various characterization techniques confirmed the presence of EMSI between Pt and defective TiO2-VO resulted in the enhanced electronic density of Pt nanoparticles. Both the modulated electronic structure of Pt and surface oxygen vacancies simultaneously promoted the activation of surface adsorbed carbon intermediates and facilitated the separation of photogenerated charges, eventually boosting the photocatalytic activity of Pt/TiO2-VO. The optimized Pt/TiO2-VO demonstrated a high quantum yield of 1.49% with high CH4 selectivity (81%), which rendered 5.8- and 1.2-fold enhancements over its counterparts of TiO2-VO and Pt/TiO2. More significantly, the EMSI also played a critical role in preserving the surface metallic Pt0 and oxygen vacancies, and in sustaining high activity of the Pt/TiO2-VO, whereas rapid catalytic deactivation are observed for both TiO2-VO and Pt/TiO2.