The Role of Pore Network Structure in the Performance of Heterogeneous Catalysts

The pore architecture and textural properties of heterogeneous catalysts affect their intrinsic and extrinsic kinetics, selectivity, and resistance to deactivation. Modelling allows the cheaper and quicker design of new catalyst products, and the optimization of the operation of existing ones. This work particularly reviews major and recent developments in pore network models (PNMs), including image-derived versions, which are a key tool for determining the impact of pore structure and mass transport on catalyst performance. It also briefly considers related areas of multi-scale modelling, first-principles modelling of active sites with DFT, intermediate-scale microkinetic modelling, and recent developments in machine-learning-based approaches. It has been seen that, for some reaction systems, PNMs can predict effectiveness factors a priori, and deliver optimized pore network designs. However, this survey also highlights issues with current models including omission of key controlling structures due to insufficient prior pore characterization, lack of the often-substantial evolution of the pore structure over the catalyst life-stages due to various on-going physical processes, and the neglect of the often-heterogeneous spatial distribution of active sites. Further, this review also considers novel experimental techniques that demonstrate, and remedy, gaps often left out from the current modelling approaches.