The vertically aligned hematite (Fe2O3) nanorods fabrication has been considered as an effective method for photoelectrochemical (PEC) water splitting. To improve the activity, two-step annealing treatment in the temperature range from 550 degrees C to 800 degrees C was proposed for the Fe2O3 nanorods synthesized by hydrothermal method. This study reveals that the OER (oxygen evolution reaction) performance increases with the annealing temperature, which yields photocurrent density of 1.036 mA cm(-2) and ABPC (applied bias photon-to-current) efficiency of 0.86% under simulated solar illumination of 100 mW cm(-2) (AM 1.5G) condition at 1.23 V vs. RHE (reversible hydrogen electrode) at 800 degrees C. The second-step short time high temperature annealing treatment has a primary contribution on the fine-tune crystallite size and the diffusion and incorporation of Sn atoms. In addition, examining the corresponding resistance properties reveal a substantial improvement in the conductivity within the hematite film and at the conducting interface, and a suppressed charge carrier recombination process. (C) 2018 Elsevier Ltd. All rights reserved.