TiO₂ nanorod arrays modified by NiFe-layered double hydroxide nanosheets for boosting photoelectrochemical water splitting

Well-aligned TiO₂/NiFe-LDH composites were successfully synthesized through the in situ electrodeposition of ultrathin NiFe-LDH nanosheets as shells on TiO₂ nanorods serving as cores. The synthesized TiO₂/NiFe-LDH composites exhibited a significant enhancement in the efficiency of photoelectrochemical (PEC) water splitting. The electrodeposition time of NiFe-LDH had a notable impact on the PEC properties of TiO₂/NiFe-LDH. With an electrodeposition duration of 40 s for the LDH, the photocurrent density of TiO₂/NiFe-LDH reached up to 1.71 mA cm⁻² at 1.23 V vs. RHE under xenon lamp irradiation, which is 1.44 times higher than that of the pristine TiO₂ nanorod photoanode. The enhanced PEC performance can be attributed to the accelerated surface water oxidation reaction facilitated by NiFe-LDH acting as a co-catalyst. Additionally, the formation of a heterojunction between TiO₂ and NiFe-LDH effectively enhances carrier separation, while the ultrathin nanosheet structure of LDH provides an increased number of active sites for the oxygen evolution reaction. The strategic utilization of NiFe-LDH to enhance TiO₂ presents a promising approach for the design of high-performance photoanodes.

NiFe-LDH modified TiO₂ composite photoanodes were successfully prepared on FTO substrates, which achieved a photocurrent density of 1.71 mA cm⁻² at 1.23 V vs. RHE under illumination, along with a high incident photon-electron conversion efficiency value of 35.19%.