Femtosecond laser mediated fabrication of micro/nanostructured TiO2 x photoelectrodes: Hierarchical nanotubes array with oxygen vacancies and their photocatalysis properties

•VOs were introduced in TiO2 nanotubes by fs-laser processing with anodization.•TiO2-x nanotubes formed on microcone’s surface, leading excellent light absorption.•Self-doping of oxygen vacancies significantly narrowed the bandgap (1.95 eV).•TiO2-x electrodes performed 15-time photocurrent and double photodegration rate.•The as-prepared photoelectrodes show great potential in photocatalytic application.