Construction and photoelectrocatalytic performance of TiO2/BiVO4 heterojunction modified with cobalt phosphate

Abstract Developing the low-cost, high performance and stable photoelectrocatalysts with water splitting performance is great important for the future energy supplement. Herein, the TiO2/BiVO4 heterojunction modified by cobalt phosphate (Co-Pi) has been successfully constructed by firstly preparing TiO2 nanopillar by the solvothermal method, followed by coupling BiVO4 films via sol-gel method and finally, the formed heterojunction is decorated with Co-Pi nanoparticles. On account of the better visible-light response, suitable band structure design and faster hole transfer effect from Co-Pi, the obtained TiO2/BiVO4/Co-Pi nanocomposite exhibits excellent activity and stability of photoelectrochemical (PEC) property, achieving a photocurrent density of 2.36 mA/cm2 at 1.23 V vs. RHE in 0.5 M Na2SO4 electrolyte, which is nine times as high as that of pure TiO2 photoanode, and possessing the best photo-corrosion resistance. Compared with the initial transient current, the photocurrent of TiO2/BiVO4/Co-Pi photoanode decreases by 25% in a steady state at 3600s, which has a better electrochemical stability, in contrast to 33% drop of TiO2/BiVO4 and 50% drop of TiO2. This route is promising as a simple method to expand the optical response range and improve the performance of PEC system effectively, also providing a guidance to construct other advanced photoelectron-catalysts for energy conversion and utilization.