Superexchange-induced Pt-O-Ti ³⁺ site on single photocatalyst for efficient H ₂ production with organics degradation in wastewater

Abstract

Efficient photocatalytic H₂ production from wastewater instead of pure water is a dual solution to the environmental and energy crisis, but due to the rapid recombination of photoinduced charge in the photocatalyst and inevitable electron depletion caused by organic pollutants, a significant challenge of dual-functional photocatalysis (simultaneous oxidative and reductive reactions) in single catalyst is designing spatial separation path for photogenerated charges at atomic level. Here, we designed a Pt-doped BaTiO₃ single catalyst with oxygen vacancies (BTPO_v) that features Pt-O-Ti³⁺ short charge separation site, which enables excellent H₂ production performance (1519 μmol·g^-1·h^-1) while oxidizing moxifloxacin (<i>k</i> = 0.048 min^-1), almost 43 and 98 times than that of pristine BaTiO₃ (35 μmol·g^-1·h^-1 and <i>k</i> = 0.00049 min^-1). The efficient charge separation path is demonstrated that the oxygen vacancies extract photoinduced charge from photocatalyst to catalytic surface, and the adjacent Ti³⁺ defects allow rapid migration of electrons to Pt atoms through the superexchange effect for H^* adsorption and reduction, while the holes will be confined in Ti³⁺ defects for oxidation of moxifloxacin. Impressively, the BTPO_v shows an exceptional atomic economy and potential for practical applications, a best H₂ production TOF (370.4 h^-1) among the recent reported dual-functional photocatalysts and exhibiting excellent H₂ production activity in multiple types of wastewaters.