Effect of surface-deposited Ti3C2Tx MXene on the photoelectrochemical water-oxidation performance of iron-doped titania nanorod array

As a promising photoanode material, TiO2 confronts two challenges, weak visible light absorption and low catalytic activity for water oxidation, which limit its photoelectrochemical performance toward water oxidation. Doping and co-catalyst deposition provide effective ways to extending the light-absorption spectral range and accelerating the water-oxidation kinetics, respectively. Herein, an efficient TiO2-based photoelectrode for water oxidation is prepared by Fe doping and electrophoretic Ti3C2Tx deposition. The Fe doping effectively extends the light absorption of TiO2 toward visible region. Owing to the excellent water oxidation activity of Ti3C2Tx, its deposition greatly accelerates the water-oxidation kinetics, which in turn enhances the photocarrier separation and injection efficiencies. The well-designed Fe-TiO2/Ti3C2Tx exhibits a photoelectrochemical current density of 1.23 mA cm−2 at 1.23 V vs. RHE, which is much higher than those of Fe-TiO2. The maximum IPCE value is enhanced from 64.7% of Fe-TiO2 to 92.8% of Fe-TiO2/Ti3C2Tx at 380 nm. Our findings provide an effective way to fabricate efficient photoanode for water oxidation and are helpful to understanding the photoelectrochemical performance of hybrid nanostructures.