Achievement of visible-light-driven Z-scheme overall water splitting using barium-modified Ta(3)N(5) as a H(2)-evolving photocatalyst

Ta(3)N(5) is one of the most promising photocatalyst candidates for solar water splitting, but it still remains challenging to achieve overall water splitting via Ta(3)N(5)-based photocatalysts regardless of whether it uses a one step or two step method. Here we will address the relatively poor photocatalytic proton reduction of Ta(3)N(5) with an effort for the promotion of charge separation via barium modification. One-pot nitridation of barium nitrate-impregnated Ta(2)O(5) precursor was adopted here for the synthesis of Ta(3)N(5) accompanied with the creation of a Ta(3)N(5)/BaTaO(2)N heterostructure and surface passivation. Due to the synergetic effect of the improved interfacial charge separation and the decreased defect density, the photocatalytic H(2) evolution rate of barium-modified Ta(3)N(5) is effectively promoted. Encouraged by this, a visible-light-driven Z-scheme overall water splitting system was successfully constructed by using the barium-modified Ta(3)N(5) as a H(2)-evolving photocatalyst, together with a PtO(x)/WO(3) and IO(3) (–)/I(–) pair as an O(2)-evolving photocatalyst and a redox mediator, respectively.