Deposition of a ZnO Nanolayer on TiO₂ Nanorods Nanoarrays with Tailored Thickness towards Boosted Photoelectrochemical Hydrogen Production Activity

Abstract

In this study, one‐dimensional (1D) core‐shell structured TiO2@ZnO nanorod arrays have been synthesised by means of a simple hydrothermal method combining with subsequently ZnO atomic layer deposition (ALD). It was found that the thickness of the ZnO shell layers can be finely controlled with 20 nm, 30 nm, 40 nm and 50 nm by simply varying the deposition times. Photoelectrochemical (PEC) water splitting tests demonstrate that the TiO2@ZnO samples with 30 nm of ZnO layer yielded the highest photocurrent density of 1.24 mA/cm2 upon AM 1.5 illumination, which was about 1.55 times higher than that of pristine TiO2. The improved PEC activity is due to the enhanced interfacial charge‐separation and transportation based on the type II heterojunction as well as the unique 1D core‐shell structure.

Integration of an Electron Transport Layer and a p‐n Heterojunction in a ZnO photoanode for Photoelectrochemical Water Oxidation

“…[26] The type-II heterojunction semiconductors with narrow bandgap and matching energy level constructed on the surface of ZnO have attracted extensive attention, and are further developed into ternary type-II heterojunction semiconductors in subsequent research. [27][28][29][30][31][32] For example, Zhou et al constructed a ZnO/TiO 2 heterojunction semiconductor with a bird's nest-like structure, and its photocurrent density reached 2.75 mA/cm 2 at 1.23 V RHE , which was 2.27 times that of pure TiO 2 . [33] This study found that the bird's nest-like three-dimensional structure increased the contact area between the photoelectrode and sunlight, and the Z-type band-matching structure effectively inhibited the recombination of photogenerated holes and electrons at the interface.…”

“…prepared Y‐doped ZnO nanorod arrays using yttrium nitrate as the Y source, and found the introduction of Y 3+ effectively reduced the transmission resistance and improved the electric conductivity [26] . The type‐II heterojunction semiconductors with narrow bandgap and matching energy level constructed on the surface of ZnO have attracted extensive attention, and are further developed into ternary type‐II heterojunction semiconductors in subsequent research [27–32] . For example, Zhou et al.…”

Preparation of Ag/CdS/MIL‐101(Cr) Composite by Dual Solvent Method and Its Photocatalytic Hydrogen Production

“…Because of the shortage of traditional energy, using solar energy photocatalysis to split water to evolve H 2 is an effective solution to solve the energy shortages. [1] At present, a variety of semiconductor photocatalysts with excellent performance have been prepared. [2][3][4][5][6] Metal-organic frameworks (MOFs) have been extensively studied because they have large specific surface area, tunable structure and high porosity.…”