Bi plasmon-enhanced mesoporous Bi2MoO6/Ti3+ self-doped TiO2 microsphere heterojunctions as efficient visible-light-driven photocatalysts

Abstract

Bi plasmon-enhanced mesoporous Bi2MoO6/Ti3+ self-doped TiO2 microsphere heterojunctions (Bi-BMO/TiO2-x) have been synthesized by a mild hydrothermal method combined with an in situ solid-state chemical reduction process, and subsequently annealed at 400 °C in N2 atmosphere. The prepared Bi-BMO/TiO2-x photocatalysts are characterized by X-ray diffraction, N2 adsorption, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results reveal that Ti3+ self-doped TiO2 is loaded on surface of mesoporous Bi2MoO6 microsphere efficiently and metallic Bi is produced for surface plasmon resonance (SPR). Under visible-light irradiation, the heterojunctions photocatalyst shows excellent photodegradation and photoelectrochemical properties of ∼95% for phenol removal rate and 20 μA/cm2 for photocurrent density, respectively, which is several times higher than that of single component. Moreover, it also has high photocatalytic oxygen production with a rate of 134 μmol h-1 g-1. The enhanced photocatalytic activities are mainly attributed to the existence of Ti3+ self-doping and heterojunction structure, which narrow the band gap to extend photoresponse to visible light region. Another reason is the influence of SPR of metallic Bi. They all promote the spatial separation and transfer of photogenerated charge carriers.