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Direct conversion of methane to acetic acid with high activity and selectivity over non-noble metal-based catalysts under mild reaction conditions remains a grand challenge. Specifically, 1.2Ni-ZSM-5 with 88.9 % isolated Ni sites achieved a high acetic acid yield of 2920 μ mol/g cat. and a remarkable selectivity up to 82.3 % from methane oxidative carbonylation. Combined with high angle annular dark field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy analyses, it was revealed that the isolated Ni species with Ni-O 6 moieties anchored in the micropores of ZSM-5 were suggested to be the active sites. The isotopic labeling experiments and monitoring of reaction intermediates demonstrated that CH 3 COOH was formed via the direct coupling of methyl radicals and carbon monoxide molecules. This work suggests that the well-designed Ni sites can promote the transformation of CH 4 to C 2+ oxygenates instead of traditional C 1 oxygenates as main products. [Display omitted] • Non-noble Ni-based catalyst can promote the oxidative carbonylation of CH 4 to C 2+ oxygenates. • 2920 μ mol/g cat. of oxygenated products can be acquired with 82.3 % of CH 3 COOH selectivity. • The catalytic performance of Ni-ZSM-5 is comparable to these noble metal-based catalysts. • Isolated Ni sites anchored on zeolites was identified as active center. • The CH 3 COOH was formed via the direct coupling of ·CH 3 radicals and CO. [ABSTRACT FROM AUTHOR]