Superexchange-induced Pt-O-Ti3+ site on single photocatalyst for efficient H2 production with organics degradation in wastewater

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 (BTPOv) that features Pt-O-Ti3+ short charge separation site, which enables excellent H2 production performance (1519 μmol·g-1·h-1) while oxidizing moxifloxacin (k = 0.048 min-1), almost 43 and 98 times than that of pristine BaTiO3 (35 μmol·g-1·h-1 and k = 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 BTPOv 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.

Dual-Functional Photocatalysis for Cooperative Hydrogen Evolution and Benzylamine Oxidation Coupling over Sandwiched-Like Pd@TiO2 @ZnIn2 S4 Nanobox

Photocatalytic hydrogen evolution (PHE) over semiconductor photocatalysts is usually constrained by the limited light-harvesting and separation of photogenerated electron-hole pairs. Most of the reported systems focusing on PHE are facilitated by consuming the photoinduced holes with organic sacrificial electron donors (SEDs). The introduction of the SEDs not only causes the environmental problem, but also increases the cost of the reaction. Herein, a dual-functional photocatalyst is developed with the morphology of sandwiched-like hollowed Pd@TiO₂ @ZnIn₂ S₄ nanobox, which is synthesized by choosing microporous zeolites with sub-nanometer-sized Pd nanoparticles (Pd NPs) embedded as the sacrificial templates. The ternary Pd@TiO₂ @ZnIn₂ S₄ photocatalyst exhibits a superior PHE rate (5.35 mmol g^-1 h^-1 ) and benzylamine oxidation conversion rate (>99%) simultaneously without adding any other SEDs. The PHE performance is superior to the reported composites of TiO₂ and ZnIn₂ S₄ , which is attributed to the elevated light capture ability induced by the hollow structure, and the enhanced charge separation efficiency facilitated by the ultrasmall sized Pd NPs. The unique design presented here holds great potential for other highly efficient cooperative dual-functional photocatalytic reactions.