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