Liquid Nitrogen Exfoliation and Nanodispersion of WS for Thermocatalysts.

The efficient and clean exfoliation of single and/or few-layer nanosheets of WS, a two-dimensional transition metal dichalcogenides, remains a significant challenge. In this study, a simple exfoliation method was proposed to produce ultrathin WS nanosheets by combining the liquid nitrogen exfoliation and nanodispersion techniques. This approach efficiently exfoliated WS into several layers of nanosheets via rapid temperature changes and mechanical stress without inducing defects or contamination. After five cycles of heating/liquid nitrogen and nanodispersion, the resulting WS nanosheets (WS-5N ND) were confirmed to have been successfully exfoliated into 1-4 layers. When applied as a promoter in a thermocatalyst for the selective catalytic reduction of NO using NH, 2V3WS/Ti (WS-5N ND) exhibited excellent NO conversion and N selectivity, along with excellent durability even in the presence of SO. This result was greater than 2V3WS/Ti (WS-5N) subjected to only liquid nitrogen exfoliation, proving the importance of the simultaneous action of both methods. This method is expected to be an important contribution to ongoing research on high-performance WS-based catalysts, thereby opening up potential opportunities for a wide range of applications.