Panda Suvendu, Maity Tanmoy, Sarkar Susmita, Manna Arun Kumar, Mondal Jagannath, Haldar Ritesh
Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500046, Telangana, India.
Haldia Institute of Technology, Department of Applied Science and Humanities, Hatiberia, ICARE Complex, Haldia, Purba Medinipur, West Bengal, 721657, India.
Nat Commun. 2025 Feb 3;16(1):1231. doi: 10.1038/s41467-025-56575-6.
In the realm of heterogeneous catalysis, the diffusion of reactants into catalytically active sites stands as a pivotal determinant influencing both turnover frequency and geometric selectivity in product formation. While accelerated diffusion of reactants can elevate reaction rates, it often entails a compromise in geometric selectivity. Porous catalysts, including metal-organic and covalent organic frameworks, confront formidable obstacles in regulating reactant diffusion rates. Consequently, the chemical functionality of the catalysts typically governs turnover frequency and geometric selectivity. This study presents an approach harnessing diffusion length to achieve improved selectivity and manipulation of reactant-active site residence time at active sites to augment reaction kinetics. Through the deployment of a thin film composed of a porous metal-organic framework catalyst, we illustrate how programming reactant diffusion within a cross-flow microfluidic catalytic reactor can concurrently amplify turnover frequency (exceeding 1000-fold) and enhance geometric selectivity ( ~ 2-fold) relative to conventional nano/microcrystals of catalyst in one-pot reactor. This diffusion-programed strategy represents a robust solution to surmount the constraints imposed by bulk nano/microcrystals of catalysts, marking advancement in the design of porous catalyst-driven organic reactions.
在多相催化领域，反应物向催化活性位点的扩散是影响产物形成的周转频率和几何选择性的关键决定因素。虽然反应物的加速扩散可以提高反应速率，但这通常需要在几何选择性上做出妥协。包括金属有机框架和共价有机框架在内的多孔催化剂在调节反应物扩散速率方面面临巨大障碍。因此，催化剂的化学功能通常决定周转频率和几何选择性。本研究提出了一种利用扩散长度的方法，以实现更高的选择性，并控制反应物在活性位点的停留时间，从而加快反应动力学。通过部署由多孔金属有机框架催化剂组成的薄膜，我们展示了如何在错流微流控催化反应器中对反应物扩散进行编程，相对于在单釜反应器中使用的传统纳米/微晶催化剂，可同时提高周转频率（超过1000倍）并增强几何选择性（约2倍）。这种扩散编程策略是克服块状纳米/微晶催化剂所带来限制的有效解决方案，标志着多孔催化剂驱动的有机反应设计取得了进展。
