This study reports the synthesis of Er-doped, Mn-doped, and Er, Mn co-doped monoclinic BiVO4 photocatalysts via a facile one-pot hydrothermal method. Er6%Mn2%/BiVO4 exhibited a larger specific surface area, bigger pore volume, and smaller average pore size compared to pure BiVO4 and single-doped BiVO4. The co-doping of Er3+ and Mn2+ ions resulted in lattice distortion and crystal particle size reduction of BiVO4, and generated a new impurity level at the bottom of the conduction band, narrowing the band gap and widening the absorption edge of visible light, thus improving the separation effici...