Preparation of hematite with an ultrathin iron titanate layer via an in situ reaction and its stable, long-lived, and excellent photoelectrochemical performance

Abstract

In this work, a facile and in situ method is proposed to prepare a high-performance photoanode with an ultrathin Fe2TiO5 layer on hematite by the reaction of tetrabutyl titanate with electro-reduced Fe film, which avoids using FeOOH film as substrate. The preparation involves 30s of direct electro-reduction (ER) of Fe film and 3min of a sol method, followed by thermal treatment. The as-prepared photoanode shows a significant enhancement of the photocurrent density to ∼2.0mA/cm2 (1.23V vs. RHE). The incorporation of a Co/Pi catalyst resulted in a photocurrent density of ∼3.05mA/cm2. The high photoelectrochemical performance can be attributed to the low microstructural defects, the better carrier separation and faster electron transfer based on electrochemical impedance spectroscopy (EIS) and Intensity-modulated photocurrent spectroscopy (IMPS) analysis. In addition, the prepared photoanode shows good stability under both alkaline and neutral conditions.