Reaction Mechanism of Methanol Conversion in Zeolite by Integrated Diffusion/Reaction Kinetics Model

ongoing

C1 Chemistry plays a crucial role in providing energy and chemical supplies while meeting environmental requirements, such as carbon neutrality to mitigate global warming and the gradual shift in the supply chain from crude oil to biomass, and other alternative carbon sources. Zeolites, as one kind of important heterogeneous catalysts, create a perfect environment to selectively and effectively convert C1 molecules to chemicals with high economic value, as for instance the transformation of methanol to olefins (MTO) or the methanol carbonylation process. However, the understanding of the reaction mechanisms of these methanol conversions in zeolites is lacking. Up till now the diffusion process of reactants, intermediates, and products in the confined spaces of zeolites has not been considered in the free energy landscape of the catalytic cycle, which leads to a discrepancy between experiments and calculations. Therefore, the proposed integrated diffusion/reaction kinetics model is an essential keystone to understand the high selectivity of zeolites in C1 chemistry. In this project, ab initio molecular dynamic (AIMD) simulations accelerated with different enhanced sampling methods will be employed to study the complete kinetics of methanol conversion in zeolites, including the processes of reactants adsorption/diffusion, reaction, and product diffusion/desorption. This should result in a complete free energy landscape, by which the parameters of zeolites that influence the selectivity of C1 chemistry will be uncovered. The final affinity of this model is to guide the modification, design, and screening of highly effective zeolite catalysts for C1 chemistry in an efficient and adequate manner.