Effects of open cell foam support on Ni-based catalysts for low concentration methane oxidation

• Structured NiO/SiC exhibits high activity and stability for lean CH 4 oxidation. • SiC enriches reactive oxygen species and improves structural stability. • SiO x -mediated charge redistribution creates electron-deficient Ni 2+ sites. • Ni 2+ sites anchor CH x intermediates and accept electrons donated by C–H cleavage. • The first C–H cleavage is the key barrier in CH 4 dehydrogenation on NiO. Low-concentration methane emitted from coal mines is both a potential energy resource and a greenhouse pollutant, but the highly diluted CH 4 stream cannot sustain stable combustion due to insufficient radical concentrations. Catalytic oxidation provides an effective utilization route, while catalytic activity and stability are frequently limited by insufficient support engineering. Herein, NiO supported on Al 2 O 3 , ZrO 2 , and SiC open cell foams were synthesized and their catalytic performances for low-concentration methane (1.0 vol% CH 4 ) oxidation were evaluated. NiO/SiC exhibited the best performance, achieving T 50 = 361.3 °C and T 90 = 401.1 °C, with negligible deactivation over 50 h at 450 °C. Combining comprehensive characterizations with DFT calculations, it was found that the SiC support synergistically improved thermal stability, enhanced reactive oxygen availability, and promoted electron-deficient Ni 2+ centers formation. During CH 4 activation, the first C–H bond cleavage is the rate-determining step in CH 4 dehydrogenation, and Ni 2+ sites act not only as geometric anchors for the intermediates but also as electronic acceptors that accommodate the donated electrons from C-H bonds cleavage. The electron-deficient Ni environment induced by SiO x -mediated interfacial charge redistribution strengthens CH x intermediates adsorption and lowers the barrier for subsequent dehydrogenation, accounting for enhanced low-temperature activity and stability. These results provide a mechanistic basis for support engineering that couples thermal regulation with oxygen dynamics and electronic modulation, enabling scalable structured catalysts for low-concentration methane abatement.