MoS₂ Quantum Dots@TiO₂ Nanotube Arrays: An Extended-Spectrum-Driven Photocatalyst for Solar Hydrogen Evolution

TiO₂ nanotube arrays (TiO₂ NTAs) decorated with molybdenum disulfide quantum dots (MoS₂ QDs) were synthesized by a facile electrodeposition method and used as a composite photocatalyst. MoS₂ QDs/TiO₂ NTAs showed enhanced photocatalytic activity compared with pristine TiO₂ NTAs for solar light-promoted H₂ evolution without adding any sacrificial agents or cocatalysts. The photocatalytic activity was influenced by the amount of MoS₂ QDs coated on TiO₂ NTAs. The optimal composition showed excellent photocatalytic activity, achieving H₂ evolution rates of 31.36, 5.29, and 1.67 μmol cm⁻² h⁻¹ corresponding to ultraviolet (UV, λ<420 nm), visible (Vis, λ≥420 nm), and near-infrared (NIR, λ>760) illumination, respectively. The improved photocatalytic activity was attributed to the decreased bandgap and the surface plasmonic properties of MoS₂ QDs/TiO₂ NTAs, which promoted electron–hole pair separation and the absorption capacity for Vis and NIR light. This study presents a facile approach for fabricating MoS₂ QDs/TiO₂ NTA heterostructures for efficient photocatalytic H₂ evolution, which will facilitate the development of designing new photocatalysts for environment and energy applications.