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

• Fe-TiO 2 /Ti 3 C 2 T x photoanode is prepared by depositing Ti 3 C 2 T x on Fe-TiO 2 nanorods. • Ti 3 C 2 T x greatly accelerates the water-oxidation kinetics on Fe-TiO 2 photoanodes. • The PEC current density of Fe-TiO 2 /Ti 3 C 2 T x can reach 1.23 mA cm−2 at 1.23 V vs. RHE. • The IPCE of 92.8% is obtained on the well-designed Fe-TiO 2 /Ti 3 C 2 T x at 380 nm. • The underlying PEC enhancement mechanism of the deposited Ti 3 C 2 T x is unveiled. As a promising photoanode material, TiO 2 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 TiO 2 -based photoelectrode for water oxidation is prepared by Fe doping and electrophoretic Ti 3 C 2 T x deposition. The Fe doping effectively extends the light absorption of TiO 2 toward visible region. Owing to the excellent water oxidation activity of Ti 3 C 2 T x , its deposition greatly accelerates the water-oxidation kinetics, which in turn enhances the photocarrier separation and injection efficiencies. The well-designed Fe-TiO 2 /Ti 3 C 2 T x 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-TiO 2. The maximum IPCE value is enhanced from 64.7% of Fe-TiO 2 to 92.8% of Fe-TiO 2 /Ti 3 C 2 T x 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. [ABSTRACT FROM AUTHOR]