Preparation of Zn-modified hematite from ZnFe alloy film for photoelectrochemical water splitting

The pristine and Zn-modified hematite electrodes are prepared from the electrodeposited Fe and ZnFe alloy films by annealing treatment. The results show that both two-step annealing treatment and Zn modification improve the photocurrent density and cause negative shift of the onset potential of photocurrent. For photoelectrochemical (PEC) water splitting, the optimum Zn content of the Zn-modified hematite photoanode is 1%. Annealed by one-step annealing treatment, the improved PEC properties of the Zn-modified hematite are mainly attributed to the increased light absorption and its higher catalytic activity for OER. Annealed by two-step annealing treatment, the enhanced PEC properties of the Zn-modified hematite are attributed to the hybrid surface states, the increased (110)/(104) ratio, and the reduced ZnO/Fe₂O₃ interface caused by Zn evaporation. By various means of characterization, the effects of Zn content and annealing regime on the morphology, structure and PEC performance of the hematite photoanodes prepared from ZnFe alloys are systematically investigated.