Enhancing Hydrogen Evolution Catalysis through Potential-Induced Structural Phase Transition in Transition-Metal Dichalcogenide Thin Sheets.

Enhancing electrocatalytic performance relies on effective phase control, which influences key catalytic properties, such as chemical stability and electrical conductivity. Traditional methods for manipulating the phase of transition-metal dichalcogenides (TMDs), including high-temperature synthesis, Li intercalation, and doping, involve harsh conditions and energy-intensive processes. This study introduces an innovative approach to crafting heterophase structures (2H-1T-WS2) in TMDs, using WS2 as a model compound, encompassing both semiconducting (2H) and metallic (1T) types through a straightforward potential activation method. Insights from in situ electrochemical Raman spectroscopy, HR-TEM, and XPS measurements reveal distinctive partial phase-transition behavior. This behavior enables the partially exposed basal plane of 2H-1T-WS2 to demonstrate superior activity in the hydrogen evolution reaction (HER), attributed to enhanced electrical conductivity and the exposure of highly active sites. The potential-induced phase transition presents promising avenues for the development of catalysts with heterophase structures.

Improvement of 3D white chocolate printing molding effect with oleogels.

This study used oleogels to resolve unsolidified white chocolate in 3D printing. Because white chocolate cannot be shaped during 3D printing, the oleogel system is used to solve this problem. The printing parameters and accuracy in a 3D printing system were investigated by using different oleogels added to white chocolate as a material to enhance chocolate extrusion solidification, monoglycerides (MAG), sucrose fatty acid ester (SE) and hydroxypropyl methylcellulose (HPMC), and their effects on rheological characterization, bridging experiments, and optimal print parameters (material formulation, nozzle height, layer height and print speed) were compared. In the rheological analysis, the viscosity recovery was more than 80% for the HPMC group and less than 80% for the MAG and SE groups. In the bridging experiment, when MAG and SE were added at more than 2%, the white chocolate could be effectively extruded and solidified, and the bridging distance could be stretched to 10 mm. The suitable printing parameters are a nozzle height of 3 mm, a layer height of 3 mm, and a printing speed of 10 mm/s. This study provides a future solution to solve the problem of extruded unsolidified chocolate.