Boosting Photoelectrochemical Water Oxidation Performance of Ti–Fe2O3 Photoanode via NH2–MIL–53(FeCo) as a Cocatalyst

Abstract

α–Fe2O3 is a promising photoanode that can be used for solar‐driven photoelectrochemical (PEC) water splitting. However, due to low carrier separation efficiency and slow water oxidation kinetics, the PEC performance of Ti–Fe2O3 is still severely hindered. Here, a novel inorganic–organic hybrid composite photoanode is prepared by depositing NH2–materials of institute Lavoisier (MIL)–53(FeCo) cocatalyst on the surface of Ti–Fe2O3 using solvothermal method. In the results, it is shown that the Ti–Fe2O3/NH2–MIL–53(FeCo) photoanode has a high photocurrent density (3.0 mA cm−2 at 1.23 V vs reversible hydrogen electrode (RHE), which is 5.1 times that of bare Ti–Fe2O3, and the initial potential of water oxidation also undergoes a negative change of about 100 mV. The separation efficiency of Ti–Fe2O3/NH2–MIL–53(FeCo) is significantly enhanced, and the charge injection efficiency increases from 17.6% to 68% at 1.23 V versus RHE. In the further research, it is suggested that the excellent PEC performance of Ti–Fe2O3/NH2–MIL–53(FeCo) may be attributed to an increase in carrier density, prolonged carrier recombination time, and an increase in exposed reactive sites. In this study, a new understanding for the design of Ti–Fe2O3 photoanodes with superior PEC performance based on metal organic framework modification is provided.