Three-dimensionally ordered macroporous Sn4+-doped TiO2 with anatase–rutile mixed phase via Pt loading by photoreduction method: enhanced photodegradation and hydrogen production performance

Abstract

In this paper, a type of three-dimensionally ordered macroporous (3DOM) composite of Sn⁴⁺-doped titanium dioxide (Sn–TiO₂) was synthesized by the colloidal crystal template technology, and Pt metal particles were successfully supported on the composite by the photoreduction method (3DOM Pt/Sn–TiO₂). The crystal structure, morphology, composition and surface physicochemical properties of 3DOM Pt/Sn–TiO₂ were characterized by various analytical methods. The characterization data showed that 3DOM Pt/Sn–TiO₂ had the typical anatase and rutile mixed phase as well as a well-ordered three-dimensional macroporous structure. After photoreduction, Pt in the composites was present mainly in the form of a simple substance, and it was evenly distributed on the surface of the 3DOM composite. Meanwhile, the local surface plasmon resonance effect (SPR) of the noble metal increased visible-light absorption of the composite. Multi-mode photocatalytic experiments showed that 3DOM Pt/Sn–TiO₂ exhibited significantly higher activity in photodegradation and photolysis for hydrogen evolution than pure anatase TiO₂. In photodegradation experiments, 3DOM Pt/Sn–TiO₂ showed the highest photodegradation activity and degradation rate. Simultaneously, the hydrogen evolution ability of 3DOM Pt/Sn–TiO₂ significantly improved in the water hydrogen production experiment. Compared with the result of P25, the hydrogen evolution capacity of 3DOM Pt/Sn–TiO₂ increased by 40 times.