Fine-tuning pulse reverse electrodeposition for enhanced photoelectrochemical water oxidation performance of α-Fe2O3 photoanodes

Abstract

High-quality hematite (α-Fe2O3) photoanodes were synthesized from a sulfate electrolyte bath by the pulse reverse electrodeposition (PRED) method. The influence of PRED parameters (viz. duty cycle, pulse period, and deposition time) was systematically investigated on the structural, optical, morphological, and photoelectrochemical properties of the films. The optimized parameters of pulse duty cycle, pulse period, and the deposition time were 20%, 10 ms, and 45 s, respectively. The granular and compact nanocrystalline morphology of the α-Fe2O3 was found to alter according to the process parameters. The α-Fe2O3 electrodes (film thickness ∼200 nm) prepared by annealing at 550 °C for 4 h followed by 800 °C for 15 min exhibited an optimum photocurrent density of 504 μA cm-2 measured at 1.23 V vs RHE in 1 M NaOH electrolyte under 100 mW cm-2 light illumination.