Synthesis, characterization and photocatalysis of AgAlO2/TiO2 heterojunction with sunlight irradiation

•A novel photocatalyst AgAlO2/TiO2 heterojunction has been successfully synthesized.•The samples were characterized using XRD, SEM and Uv–vis analysis technologies.•The mass ratio of the AgAlO2/TiO2 dominated the photocatalytic activity.•The decomposition of formaldehyde reached 97.8% under sunlight irradiation for 90 min.

A novel photocatalyst AgAlO2/TiO2 with a p–n heterojunction structure was synthesized through the method that combined sol–gel and ion exchange. The as-synthesized samples were characterized by XRD, SEM and UV–vis. The photocatalytic activity of as-synthesized sample was evaluated and the possible mechanism was discussed. As-synthesized AgAlO2/TiO2 (in mass ratio of 90/10) exhibited remarkably high photocatalytic activity of 97.8% in decomposing formaldehyde under sunlight irradiation for 90 min. Our work provided a basic experimental process for AgAlO2/TiO2 heterojunction and explored the connection between p–n heterojunction and photocatalysis, which will possess a broad prospect in terms of the applications in improving indoor air quality.