Solar light driven pure water splitting of B-doped BiVO4 synthesized via a sol-gel method

The lower part of VBs mainly consists of O 2p orbitals and the hybridizations between O 2p and V 3d for BiVO4 as shown in figure a. The UV-vis diffuse reflectance spectra of BiVO4 with different boron doping level showed that these samples have almost no difference in the band gap energy which demonstrated there is less probability of substitutional B entering into Bi, V and O sites in the BiVO4 lattice. At the same time the boron doping reduces obviously the electrochemical impedance and results a remarkable increasing of photocurrent for BiVO4 photoanode. As displayed in figure d, some weak chemical bonds form between the doped boron ions and corners of VO4 tetrahedrons. Thus the interstitial boron doping plays a key role in improve the poor electron transport properties to obtain desire photocurrent. In addition, we suggest that the other small ions (e.g. Li, Be ions) would be another possible way to enhance the photocatalytic performance of BiVO4 by interstitial doping among VO4 tetrahedrons.