Key Role of Catalyst Pore Structure in Nonthermal Plasma-assisted Heterogeneous Catalysis

This review systematically evaluates the critical role of catalyst pore architecture in nonthermal plasma (NTP)-assisted heterogeneous catalysis, focusing on its impact on reactive species diffusion, surface plasma micro-discharge behaviors, and reaction performances in typical NTP catalytic processes such as CO2 hydrogenation and ammonia synthesis. Current research findings suggest porous catalyst structures can enhance local electric fields, with pore sizes approaching the Debye length promoting micro-discharges within the pores. Hierarchical porosity is beneficial to the NTP systems, improving not only catalyst dispersion but also the local mass transfer of plasma-induced reactive species (the improved accessibility of active sites), and thus the enhanced reaction performance. Case studies highlight that optimized pore structures (e.g., hierarchical mesoporous-microporous frameworks) significantly boost CO2 conversion to methane and methanol under mild conditions. In ammonia synthesis, microporous materials like ZIF-8 and gyroid mesoporous silica achieve high ammonia yields. However, mechanistic insights into the complex role of catalyst pore structures in balancing species diffusion under plasma, tuning the interaction between active sites and plasma-induced species and optimizing energy efficiency are still lacking. Future research in this field should place greater emphasis on hierarchical mesoporous-microporous structures with large pore diameters, as well as the synergy between discharge and confined catalysis.