Rapid Fabrication of Oxygen Defective α-Fe2O3(110) for Enhanced Photoelectrochemical Activities

Abstract

Defect engineering is increasingly recognized as a viable strategy for boosting the performance of photoelectrochemical (PEC) water splitting by metal oxide-based photoelectrodes. However, previously developed methods for generating point defect associated with oxygen vacancies is rather time-consuming. Herein, high density oxygen deficient α-Fe2O3 with dominant (110) crystal plane is developed in very short timescale of 10 minutes by employing aerosol-assisted chemical vapor deposition and pure nitrogen as gas carrier. The oxygen defective film exhibits almost 8 times higher photocurrent density compared to hematite photoanode with low concentration of oxygen vacancies which is prepared in purified air. The existence of oxygen vacancies improves light absorption ability, accelerates charge transport in the bulk of film, and promotes charge separation at electrolyte/semiconductor interface. DFT simulations verify that oxygen defective hematite has a narrow band gap, electron-hole trapped centre, and strong adsorption energy of water molecules compared to that of pristine hematite. This strategy might bring PEC technology another step further towards large-scale fabrication for future commercialization.