| Summary: | As one of the widely studied semiconductor materials, titanium dioxide (TiO<sub>2</sub>) exhibits high photoelectrochemical (PEC) water-splitting performance as well as high chemical and photo stability. However, limited by a wide band gap and fast electron-hole recombination rate, the low solar-to-hydrogen conversion efficiency remains a bottleneck for the practical application of TiO<sub>2</sub>-based photoelectrodes. To improve the charge separation and water oxidation efficiency of TiO<sub>2</sub> photoanodes, antimonene, a two-dimensional (2D) material obtained by liquid-phase exfoliation, was assembled onto TiO<sub>2</sub> nanorod arrays (TNRAs) by a simple drop-coating assembly process. PEC measurements showed that the resulting 2D Sb/TiO<sub>2</sub> photoelectrode displayed an enhanced photocurrent density of about 1.32 mA cm<sup>−2</sup> in 1.0 M KOH at 0.3 V vs. Hg/HgO, which is ~1.65 times higher than that of the pristine TNRAs. Through UV-Vis absorption and electrochemical impedance spectroscopy measurements, it was possible to ascribe the enhanced PEC performances of the 2D Sb/TiO<sub>2</sub> photoanode to increased absorption intensity in the visible light region, and improved interfacial charge-transfer kinetics in the 2D Sb/TiO<sub>2</sub> heterojunction, which promotes electron-hole separation, transfer, and collection.
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