Size Control of MoS<i>_x</i> Catalysts by Diffusion Limitation for Electrocatalytic Hydrodesulfurization

Electrochemical hydrodesulfurization technology is a promising approach to remove sulfur compounds from fossil fuels, having the advantages of moderate operating condition, low energy consumption, and high automation. This method is still in the research and development stage, and the desulfurization efficiency needs to be improved. Here, we report an attempt to improve the desulfurization efficiency by increasing the active sites of catalysts. The amorphous MoSx are chosen as the catalysts and synthesized by the electrodeposition method at diffusion-limited conditions, which is regulated by either increasing the deposition potential or by adding glycerol into the electrolyte. With the decrease of chemical diffusion, the morphology of MoSx catalysts changes from continuous lamellae to dispersed nanoparticles on the surface of carbon cloth. Owing to the extensive exposure of the bridging sulfur groups S22– and undercoordinated Mo­(V) regions, the MoSx particles exhibit a more than two times increase of the desulfurization efficiency, reaching 22.5% in the electrochemical hydrodesulfurization. This study shows that structure optimization of catalysts by diffusion control is a facile and general strategy to improve reaction efficiency, which may be applied to various catalysts

The Role of the Liquid–Liquid Interface in the Synthesis of Nonequilibrium Crystalline Wurtzite ZnS at Room Temperature

In this research, the role that the organic–inorganic liquid interface plays in the synthesis of nonequilibrium crystalline materials is investigated. A hierarchical nanocrystalline film of wurtzite ZnS, the high-temperature stable phase, is successfully prepared at room temperature by an interfacial in situ fabrication process. The organic–inorganic liquid interface constructed by n-hexane and water acts as the reaction zone for the synthesis of ZnS nanocrystalline film. A series of experimental results have proved that the liquid–liquid interface is the key factor for wurtzite ZnS formation at room temperature without any additive. The ZnS film consists of core–shell subunits characterized by ZnS nanoparticles around an organic core. Between the liquid–liquid interface, the core–shell subunits are coupled onto the surface of a SAM-modified substrate by terminal amino groups, so that the ZnS nanocrystalline film is formed by a layer-by-layer mode. This research brings forward a feasible route for synthesizing wurtzite ZnS in one-step process at room temperature and provides some beneficial information for studying the structural kinetics of nonequilibrium crystalline synthesis