Pore-Confinement Modulates Co3O4/ZSM-5 Redox and Oxygen Mobility for Efficient Propane Oxidation

The directional design of efficient catalysts for volatile organic compounds (VOCs) abatement remains effective yet challenging. Here, 3   wt% Co 3 O 4 catalysts supported on ZSM-5, Beta, MCM-41, and HY supports were constructed to elucidate the pronounced influence of pore confinement on catalyst redox behavior and catalytic activity. The micropore channels of ZSM-5 stabilizes appropriately sized CoO x clusters and enriches surface Co 3+ , thereby promoting low-temperature Co 3+ /Co 2+ cycling and lattice-oxygen migration, which endows Co 3 O 4 /ZSM-5 with superior performance in propane total oxidation. The T 50 of Co 3 O 4 /ZSM-5 catalyst is 260 ℃, which is 20 ℃ and 100 ℃ lower than those of Co 3 O 4 /Beta and Co 3 O 4 /MCM-41, respectively; it also exhibits E a of 37.6 kJ·mol -1 , specific surface activity at 260 ℃ of 21×10 -8 mol·m -2 ·s -1 , and TOF of 1.2×10 -2 s -1 , together with excellent water resistance and stability. By contrast, the wide mesopores of MCM-41 induce Co 3 O 4 agglomeration, while the overly strong confinement exerted by HY and Beta supports over-stabilizes Co 2+ and tightly bound lattice oxygen, both unfavorable for oxidation. DFT calculations further confirm that Co 3 O 4 confined in ZSM-5 exhibits the strongest O 2 activation and the lowest barriers for O 2 dissociation, CO oxidation, and the initial O-insertion/H-abstraction/C-C bond cleavage steps in propane. Overall, this work offers a new avenue for designing efficient, water-tolerant catalysts for propane oxidation.