Monolayer MoS₂ on TiO₂ nanorods for enhanced electrocatalytic hydrogen evolution reaction

The core-shell nanostructures of TMDCs and another semiconductor has been attracted much attention due to high surface-to-volume ratio and excellent electrocatalytic hydrogen evolution reaction (HER). Futhermore, number of TMDCs layer is an important factor that remarkably have an influence on the catalytic activity, therein monolayer(ML) is basically requirement. Herein, we have fabricated 2D@1D nanostructure; core of TiO₂ nanorods and shell of monolayer MoS₂. Firstly, TiO₂ NRs was grown on graphite foil by hydrothermal method. Then, TiO₂ was conformally covered by ML MoS₂ using metal organic chemical vapor deposition. A density functional theory was used to investigate the influence of TiO₂ on hydrogen Gibbs free energy (ΔG_H) of basal plane MoS₂. When ML MoS₂ composite with TiO₂, the ΔG_H is closer to 0 eV, indicating that basal plane of ML-MoS₂ become more catalytically effective for HER. The onset overpotential of 190 mV and Tafel slope of 102 mV/dec were obtained for this kind of hetero-structural, which are much lower than that of nanoscale pristine MoS₂, in agreement with theoretical simulation result.