Activation and Conversion of Methanol over M@SixCyBz Catalysts: Revealing the Impact of Boron Concentration and Metal Types on Activity and Selectivity Regulation.

To address the challenges of poor stability and low product selectivity associated with metal catalysts in the CH3OH to CHOOCH3 reaction, innovative M@SixCyBz catalysts were constructed for the first time. In this work, encapsulated M@SixCyBz catalysts (Sc@Si12C12, Sc@Si8C12B4, Sc@Si4C12B8, Si8C12B4, Cr@Si8C12B4, and Mn@Si8C12B4) are designed. First, molecular dynamics simulations demonstrate that M@SixCyBz catalysts exhibit high stability. Second, the mechanism of direct dehydrogenation of CH3OH to CHOOCH3 is systematically explored, the relevant data of each elementary reaction are calculated, and the reaction pathway is determined based on density functional theory (DFT). Finally, the electronic properties are calculated and analyzed. The results suggest that boron concentration can effectively regulate the product distribution and catalytic activity of CH3OH conversion, and the metal types can affect the activity of CHOOCH3 formation. Additionally, it is observed that the average charges of the carbon atoms at the reaction center of M@SixCyBz catalysts can be used as a descriptor for both activity and selectivity in CHOOCH3 formation. Among them, Cr@Si8C12B4 exhibits the highest activity for producing CHOOCH3. The models and calculation results can facilitate high-value utilization of CH3OH in the future.