Titanate quantum dots-sensitized Cu2S nanocomposites for superficial H2 production via photocatalytic water splitting

Abstract

TiO2 quantum dots-sensitized Cu2S (Cu2S/TiO2) nanocomposites with varying concentration of TiO2 QDs are synthesized via a facile two-stage hydrothermal-wet impregnation method. X-ray diffraction analysis confirms the formation of Cu2S and TiO2with chalcocite and anatase phases, respectively. The observed shoulder-like absorption peaks indicate the UV–visible light-driven properties of the composite. Morphological analysis reveals that the fabricated Cu2S/TiO2 composite consists of Cu2S with a nano rod-like shape (average length and width of ∼856 and ∼213 nm, respectively) and nanosheets-like structures (average length and width of ∼283 and ∼289 nm, respectively), whereas the TiO2 is formed as quantum dots with a size range of 8.2 ± 0.4 nm. Chemical state analysis shows the presence of Cu+, S2−, Ni2+, and O2− in the nanocomposite. The H2 evolution rate over the optimized photocatalyst is found to be ∼45.6 mmol h−1g−1cat under simulated solar irradiation, which is around 5 and 2.4-fold higher than that of the pristine TiO2 and Cu2S, respectively. Continuous H2 production for 30 h is achieved during time-on-stream experiments, demonstrating the excellent stability and durability of the Cu2S/TiO2 photocatalyst for large-scale applications.