Cyclic voltammetry - A promising approach towards improving photoelectrochemical activity of hematite

Understanding the effect of electrochemical reaction on a particular material at the nanoscale level is essential for the application of solar conversion technology. Herein, electrochemical cyclic voltammetry (CV) treatment was applied on the alpha-Fe2O3 thin films by varying the number of cycles between 0 and 100. The thorough investigation provides insight into the modifications on the properties of the CV-treated films. The performance of pristine and CV-treated alpha-Fe2O3 as photoanodes are evaluated in the photoelectrochemical (PEC) water splitting cell. Consecutive CV scans up to the optimum number of cycles (50 cycles) promote the photocurrent density, where the photocurrent value at 0.6 VAg/AgCl becomes about 1.5 times higher than the pristine alpha-Fe2O3. This remarkable enhancement in PEC performance is due to the synergistic effect between the change of crystal orientation, the enhancement of surface oxygen vacancies and the increase of free charge carrier density. Our findings provide valuable information of possible pathway for improving the photoelectrochemical performance of a photoanode. (C) 2020 Elsevier B.V. All rights reserved.