At low pH, the BiVO 4 surface positively charged by adsorbing protons and the surface charge density σ = 30.3 µC/cm 2 . At high pH, the BiVO 4 surface negatively charged by the desorption proton from terminal Bi 7f OH 2 and σ = -30.3 µC/cm 2 . Detailed descriptions of the computational setup are given in the ESI. †When looking at the structure of EDLs, it is found that BiVO 4 /NaCl interface are very different from those of rutile oxide TiO 2 and SnO 2 , due to a weaker water adsorption energy.