Built-in electron transport channels and interfacial ions doping in BiVO4 modified with isolated Ni atoms anchored on carbon hollow matrix for boosting charge separation and transport efficiency

Abstract

Here, a novel heterostructure with ions doped interfaces and electrons transport channels is firstly fabricated through a simple solid solution drying and calcination method, in which Ni atoms anchored on N-doped graphitic carbon hollow matrix was thoroughly covered by Mo, W co-doped BVO films (Mo, W: BVO/Ni@NGC). With the solidification of Mo, W: BVO during the calcination treatment, the carbon hollow matrix undergoes a crystal transformation from amorphous to graphitized, which should be beneficial for the electrons transport. The photocurrent density of Mo, W: BVO/Ni@NGC reaches 4.95 mA/cm2 at 1.23 V vs RHE in the absence of hole scavengers and oxidation co-catalysts. Experimental results demonstrated that Ni and NC contribute greatly to charge transport efficiency (ηtra) but have little influence on the charge separation efficiency (ηsep). The density functional theory (DFT) calculations have been performed to explore the origin of enhanced ηsep. Theoretical results demonstrated that interfacial Ni ions doping will result in a built-in electric field, which plays a major role in the improving of ηsep. Thus, the probable charge transfer mechanism of Mo, W: BVO/Ni@NGC is proposed, which should be valuable for the design of efficient photocatalysts.