Coating-loading-induced structure-transport-reaction coupling in TS-1/SiC foam catalysts for continuous phenol hydroxylation

Structured-catalyst performance depends on a balance between active-phase density and transport accessibility, yet this trade-off remains insufficiently quantified for TS-1-coated SiC foams. Here, binder-free TS-1/SiC catalysts with coating loadings of 0.09, 0.18, and 0.25 g cat /mL SiC were evaluated for continuous phenol hydroxylation with H 2 O 2 using complementary activity normalization, multiscale pore characterization, kinetic analysis, and μ-CT-based Computational Fluid Dynamics (CFD). Increasing coating loading increased BET surface area and total pore volume through the addition of porous TS-1, but simultaneously constricted millimeter-scale open-flow channels. As a result, the three coating loadings examined here reveal a flow-dependent trade-off between active-phase inventory and apparent utilization. By comparing phenol-processing rates on both coating-mass and reactor-volume bases, and relating them to multiscale pore characterization, this study distinguishes the benefit of adding porous TS-1 from the diminishing performance gains at higher loadings. Combining apparent kinetic analysis with μ-CT-based CFD further links coating loading to changes in open-channel geometry, flow distribution, and local reaction rates. Together, these analyses provide a structure-transport-reaction basis for selecting coating loading under specific operating conditions, while showing that the tested range does not establish a universal optimum.