Fabrication of Porous Cu-Doped BiVO₄ Nanotubes as Efficient Oxygen-Evolving Photocatalysts

We introduce a facile route to fabricate one-dimensional (1D) porous Cu2+-doped BiVO4 (Cu-BVO) nanotubes with uniform size distribution and high structural stability. First, an electrospinning technique was developed to prepare the sacrificial template of polyacrylonitrile (PAN) nanofibers with a smooth surface. Second, a conformal layer of Cu-BVO nanoparticles was coated onto the PAN template through a solvothermal method to obtain the solid core–shell precursor which was finally converted into the product of porous Cu-BVO nanotubes with thermal treatment. Both experimental characterizations and theoretical calculations based on the density functional theory (DFT) calculations have revealed the crucial functionality of the appropriate band structure of the Cu2+-doped nanostructure and introduced beneficial defect states by Cu doping, which boosts light absorption and promotes charge migration and separation and therefore results in highly efficient photocatalytic O2 evolution with visible-light irradiation. As a result, the porous nanotube photocatalyst with an optimal Cu2+ doping of 5.0% exhibits an average O2 evolution rate of 350.2 μmol h–1 g–1, about 2.4 times more than that of pristine BVO nanotubes.