Electrochemical growth and characterization of micro/nanostructured SnOx with crater-like morphology

•Hierarchical SnOx micro/nanostructures were obtained by anodization.•The mechanism of the formation of such crater-like structures is discussed.•Annealing at 200 °C leads to the formation of SnO and Sn3O4 within the SnOx matrix.•The material exhibit promising photocatalytic activity under solar irradiation.