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Abstract The undesirable loss of methane (CH₄) at remote locations welcomes approaches that ambiently functionalize CH₄on‐site without intense infrastructure investment. Recently, we found that electrochemical oxidation of vanadium(V)‐oxo with bisulfate ligand leads to CH₄activation at ambient conditions. The key question is whether such an observation is a one‐off coincidence or a general strategy for electrocatalyst design. Here, a general scheme of electrocatalytic CH₄activation with d⁰early transition metals is established. The pre‐catalysts’ molecular structure, electrocatalytic kinetics, and mechanism were detailed for titanium (IV), vanadium (V), and chromium (VI) species as model systems. After a turnover‐limiting one‐electron electrochemical oxidation, the yielded ligand‐centered cation radicals activate CH₄with low activation energy and high selectivity. The reactivities are universal among early transition metals from Period 4 to 6, and the reactivities trend for different early transition metals correlate with their d orbital energies across periodic table. Our results offer new chemical insights towards developing advanced ambient electrocatalysts of natural gas. 

Abstract Although most class (b) transition metals have been studied in regard to CH₄activation, divalent silver (Ag^II), possibly owing to its reactive nature, is the only class (b) high‐valent transition metal center that is not yet reported to exhibit reactivities towards CH₄activation. We now report that electrochemically generated Ag^IImetalloradical readily functionalizes CH₄into methyl bisulfate (CH₃OSO₃H) at ambient conditions in 98 % H₂SO₄. Mechanistic investigation experimentally unveils a low activation energy of 13.1 kcal mol⁻¹, a high pseudo‐first‐order rate constant of CH₄activation up to 2.8×10³ h⁻¹at room temperature and a CH₄pressure of 85 psi, and two competing reaction pathways preferable towards CH₄activation over solvent oxidation. Reaction kinetic data suggest a Faradaic efficiency exceeding 99 % beyond 180 psi CH₄at room temperature for potential chemical production from widely distributed natural gas resources with minimal infrastructure reliance. 

The roles of unforgiving H 2 SO 4 solvent in CH 4 activation with molecular catalysts have not been experimentally well-illustrated despite computational predictions. Here, we provide experimental evidence that metal-bound bisulfate ligand introduced by H 2 SO 4 solvent is redox-active in vanadium-based electrocatalytic CH 4 activation discovered recently. Replacing one of the two terminal bisulfate ligands with redox-inert dihydrogen phosphate in the pre-catalyst vanadium (V)-oxo dimer completely quenches its activity towards CH 4 , which may inspire environmentally benign catalysis with minimal use of H 2 SO 4 .