H₂ O-Built Proton Transfer Bridge Enhances Continuous Methane Oxidation to Methanol over Cu-BEA Zeolite

Direct oxidation of methane to methanol (DMTM) is a big challenge in C₁ chemistry. We present a continuous N₂ O-DMTM investigation by simultaneously introducing 10 vol % H₂ O into the reaction system over Cu-BEA zeolites. Combining a D₂ O isotopic tracer technique and ab initio molecular dynamics (AIMD) simulation, we for the first time demonstrate that the H₂ O molecules can participate in the reaction through a proton transfer route, wherein the H₂ O molecules can build a high-speed proton transfer bridge between the generated moieties of CH₃ ^- and OH^- over the evolved mono(μ-oxo) dicopper ([Cu-O-Cu]²⁺ ) active site, thereby pronouncedly boosting the CH₃ OH selectivity (3.1→71.6 %), productivity (16.8→242.9 μmol g_cat ^-1  h^-1 ) and long-term reaction stability (10→70 h) relative to the scenario of absence of H₂ O. Unravelling the proton transfer of H₂ O over the dicopper [Cu-O-Cu]²⁺ site would substantially contribute to highly efficient catalyst designs for the continuous DMTM.