Evaluation of the collaboration between intrinsic activity and diffusion: a descriptor for alkene epoxidation catalyzed by TS-1

TL;DR

The paper introduces a new descriptor to evaluate how catalyst activity and diffusion work together in alkene epoxidation reactions.

Contribution

A novel descriptor, Ra/d, is proposed to quantify the collaboration between intrinsic activity and diffusion in TS-1 catalysts.

Findings

The Ra/d descriptor successfully explains the catalytic performance of various TS-1 catalysts.

Optimal Ra/d values correspond to peak epoxidation performance due to balanced activity and diffusion rates.

Abstract

The systemic evaluation of the collaboration between intrinsic activity of active sites and the substrate/product diffusion rate is a key challenge for rational optimization of reaction performance in alkene epoxidation. Herein, we constructed a series of TS-1 catalysts with adjustable local microenvironments around active sites to explore their performance in alkene epoxidation. This was achieved by controlling the contributions of classical and non-classical routines during the crystallization process. Based on the characterization of active sites, product diffusion and their alkene epoxidation activity, we proposed a descriptor, Ra/d, for quantitative evaluation of the collaboration between intrinsic activity and product diffusion in TS-1 catalysts. This descriptor successfully explains the catalytic performance of various TS-1 catalysts including commercial TS-1 and guides further improvement of TS-1 in different alkene epoxidations. The optimal Ra/d is found in various epoxidations, corresponding to peak epoxidation performance across different substrates due to the well-balanced intrinsic activity and diffusion rate.

The systemic evaluation of the collaboration between intrinsic activity of active sites and the substrate/product diffusion rate is a key challenge for rational optimization of reaction performance in alkene epoxidation.

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