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

• Published in: Journal of alloys and compounds 2021-01, Vol.852, p.156757, Article 156757
• Main Authors: Arzaee, Nurul Affiqah, Mohamad Noh, Mohamad Firdaus, Halim, Azhar Ab, Faizal Abdul Rahim, Muhammad Amir, Haziqah Mohd Ita, Nur Suraya, Mohamed, Nurul Aida, Farhana Mohd Nasir, Siti Nur, Ismail, Aznan Fazli, Mat Teridi, Mohd Asri
• Format: Article
• Language: English
• Subjects: Carrier density; Charge density; Crystal structure; Current carriers; Cyclic voltammetry; Electrochemistry; Hematite; Iron oxides; Lattice vacancies; Photoelectric effect; Photoelectric emission; Photoelectrochemical water splitting; Semiconductors; Silver chloride; Synergistic effect; Thin films; Voltammetry; Water splitting; α-Fe2O3
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156757

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 α-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 α-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 α-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. [Display omitted] •Cyclic voltammetry treatment enhances PEC performance of α-Fe2O3 by 1.5 times.•Change of crystal orientation improve electron mobility and hole trapping behaviour.•Surface oxygen vacancies generated by CV treatment facilitate water adsorption.•CV scanning induces greater free carrier density in the film.