Electronic structure calculations of I and Mn doped BiOCl with modified Becke–Johnson potential

•TB-mBJ potential improves the calculated band gaps of the pure and doped BiOCl.•Calculated band gap of BiOCl is 3.40 eV, being in accord with the experimental value.•Band gap of co-doped BiOCl with I and Mn is decreased to 2.21 eV.

The electronic structures of pure, I doped, Mn doped, and I and Mn co-doped BiOCl are calculated by the first-principles method with the Tran–Blaha modification of the Becke–Johnson potential. The calculated band gaps of the pure as well as doped BiOCl are greatly improved compared with the results calculated using the generalized gradient approximation. Specifically, the calculated band gap of pure BiOCl is improved to 3.40 eV, being in good agreement with the experimental value of 3.46 eV. The results also show that the band gap of I and Mn co-doped BiOCl is the narrowest (2.21 eV) among the researched systems and has a strong ability for oxidation. This indicates that I and Mn co-doped BiOCl is a potential material for visible light photocatalysis.