Effect of tetravalent ions dopants and CoO surface modification on hematite nanorod array for photoelectrochemical degradation of Orange-II dye

•Tetravalent ion doped Fe2O3 photoanodes were fabricated using hydrothermal method.•Zr–Fe2O3 exhibits improved Jph = 1.37 mA cm−2 than (Sn and Ti) doped samples.•CoOx modification exhibits highest jph = 1.78 mA cm2 and 97% degradation efficiency.•Possible charge transfer mechanism during dye degradation is proposed.