Photocatalytic properties of MIn(WO4)2 (M = Li, Na, and K)

Abstract

MIn(WO4)2 (M = Li, Na, and K) with InO6 and WO6 octahedra were synthesized via a conventional solid-state reaction method. The photophysical and photocatalytic properties were studied. Compared with WO3, which is unable to evolve H2 from an aqueous CH3OH solution under illumination, the three materials can evolve H2 and O2 from aqueous solutions with CH3OH and AgNO3 sacrificial reagents, respectively. The activity order of photocatalytic H2 evolution is NaIn(WO4)2 > LiIn(WO4)2 > KIn(WO4)2 under irradiation (λ > 200 nm). Under irradiation (λ > 300 nm), however, LiIn(WO4)2 has a high activity for photocatalytic H2 evolution over NaIn(WO4)2. It is also noteworthy that LiIn(WO4)2 and NaIn(WO4)2 exhibit the ability to split pure water. The results suggest that the bottoms of the conduction bands in these photocatalysts are raised to meet the potential requirements of photocatalytic H2 evolution.