Visible light illuminated high-performance WO3-TiO2-BiVO4 nanocomposite photoanodes capable of energy self-storage for photo-induced cathodic protection

In this work, WO3-TiO2-BiVO4 nanocomposite photoanodes are prepared, enabling photoelectrochemical cathodic protection (CP) under visible light illumination, while the energy self-storage capability makes the photo-induced CP functional in darkness. The outer BiVO4 layer causes an enhanced optical absorption of visible light for photoelectrochemical reaction. The inner WO3 layer is charged with photoelectrons and discharged in darkness. The nanocomposite photoanode can cathodically polarize 304 stainless steel by 300 mV compared to its corrosion potential under visible light. In darkness, the stainless steel can also be polarized by 130 mV cathodically in chloride solutions for effective corrosion protection.