Photocatalytic properties of SnO2/MoO3 mixed oxides and their relation to the electronic properties and surface acidity

Abstract

The wet impregnation method was used to synthesize SnO2/MoO3 heterojunctions containing different amounts of Mo (5, 25 and 50 wt%). The materials obtained were characterized and their photocatalytic properties were evaluated in the photodegradation of methylene blue (MB) dye. The presence of superficial Lewis and Bronsted acid sites enhanced in photocatalytic efficiency of the materials. The order of photocatalytic activity in MB photodegradation was MoO3 > SnO2/MoO3-50 % > SnO2/MoO3-25 % > SnO2/MoO3-5% > SnO2, demonstrating that MoO3 acts as a modulator of acidity and this behavior directly influences the photocatalytic performance. In the photodegradation study, the physical mixture of SnO2+MoO3-25 % provided lower performance values than the heterojunction SnO2/MoO3-25 %, highlighting the importance of the appropriate synthesis of these materials.