Ambient catalyst-free conversion of methane to methanol by water radical cations

Methane combustion contributes 30% to global warming, making its conversion to cleaner chemicals a critical challenge. Here, we report a catalyst-free ambient conversion of methane to methanol with a remarkable yield exceeding 650 millimoles per hour and a high conversion rate of ~35%, achieved using in situ–generated water dimer radical cations, ( H 2 O ) 2 + · , in a specially designed batch reactor operating under mild conditions. In a single run, the reactor was typically operated for 10 minutes. The atom efficiency for hydrogen in our approach for methanol synthesis is ~67%. Hydrogen gas is the by-product, produced at a rate of over 2 millimoles per hour. Compared to the previously reported catalytic methods, our production yields are up by between 10 2 and 10 6 times depending on the literature method. This breakthrough enables clean, energy-efficient methane conversion without unwanted oxidation by-products, offering substantial environmental and economic benefits beyond combustion.