Efficient charge transfer on the tunable morphology of TiO2/MoS2 photocatalyst for an enhanced hydrogen production†
Abstract
The TiO2/MoS2 heterostructure consisting of varying concentrations of layered MoS2 on TiO2 of different morphology was fabricated successfully by a simple hydrothermal method. In this work, we employed TiO2 with different morphologies (commercial, nanotube, hierarchical, and nanosheets) for the synthesis of TiO2/MoS2 to examine the effect of morphology on hydrogen evolution trend. In particular, the photoinjected electron lifetime was greatly influenced by the structural pattern of the photocatalyst, as photoluminescence spectroscopy study revealed superior electron transfer efficiency in TiO2 nanosheets of the composite. The structure and optical properties of the as-prepared TiO2/MoS2 hybrid materials were confirmed by XRD, SEM, TEM, and PL studies. The hybrid materials indicated the heterostructure formation in the fine-tuned MoS2–TiO2 composite. The resultant TiO2/MoS2 showed good photocatalytic response than the pristine TiO2 and MoS2. Furthermore, at optimized MoS2 to TiO2 ratio in the composite, a series of photocatalysts were screened, such as TiO2 (commercial)/MoS2, TiO2 (nanotube)/MoS2, TiO2 (hierarchical)/MoS2 and TiO2 (nanosheets)/MoS2 with 2 wt% content of MoS2, and 29.71, 41.33, 65.54 and 77.41 μmol h−1 g−1 of hydrogen evolution was found, respectively. TiO2 (nanosheet)/MoS2 showed the highest rate of hydrogen evolution activity among them, and the introduction of MoS2 to TiO2 decreased the rate of charge carrier recombination and increased the hydrogen evolution activity. While promising, these approaches consisting of novelty that includes low cost, simple synthesis process, chemically robust and effective charge transfer pathways have shown to be effective for solar energy conversion to the clean fuel hydrogen production.