Search for: All records

MXenes are a new family of two-dimensional carbides and/or nitrides. Their 2D surfaces are typically terminated by O, OH and/or F atoms. Here we show that Ti₃C₂T_x—the most studied compound of the MXene family—is a good acid catalyst, thanks to the surface acid functionalities. We demonstrate this by applying Ti₃C₂T_xin the epoxide ring-opening reaction of styrene oxide (SO) and its isomerization in the liquid phase. Modifying the MXene surface changes the catalytic activity and selectivity. By oxidizing the surface, we succeeded in controlling the type and number of acid sites and thereby improving the yield of the mono-alkylated product to >80%. Characterisation studies show that a thin oxide layer, which forms directly on the Ti₃C₂T_xsurface, is essential for catalysing the SO ring-opening. We hypothesize that two kinds of acid sites are responsible for this catalysis: In the MXene, strong acid sites (both Lewis and Brønsted) catalyse both the ring-opening and the isomerization reactions, while in the Mxene–TiO₂composite weaker acid sites catalyse only the ring-opening reaction, increasing the selectivity to the mono-alkylated product.