Enhanced hydrogen evolution performance of ultra thin nanoslice/nanopetal structured XS{sub 2} (X = W, Mo): From experiment to theory

The production of H{sub 2} through water splitting to make the reaction process economical and friendly has attracted a lot attention. In this work, we synthesized the novel well-defined nanostructured WS{sub 2}/MoS{sub 2} composite for using as the electrocatalyst of hydrogen evolution. The final obtained nanoslice/nanopetal nanostructured WS{sub 2}/MoS{sub 2} composite possessed massive active sites that originated from its well-defined hierarchical structure with densely stacked MoS{sub 2} nanopetals. The synthesized composite exhibited significantly enhanced hydrogen evolution reaction (HER) activity and clearly superior to the pristine MoS{sub 2}/WS{sub 2}. With the purpose to give a theoretical explanation of the corresponding enhancement mechanism, the first-principles investigation based on the density functional theory was further employed to survey the electronic properties of different structures. Charge density difference and Bader charge analyses revealed that electrons could directional transfer from WS{sub 2} to MoS{sub 2} and provided an “electron-rich” environment, which was beneficial to the improvement of HER efficiency. These analytical methods will necessarily offer new angles to explain the enhancement mechanism of HER processes regarding the interaction between WS{sub 2} and MoS{sub 2}, which can accurately elucidate the reason why composite structure exhibits a better HER performance based on the experimental results.