Decatungstate-doped Ce-MOF for methane photooxidation

Direct conversion of methane into C1 oxygenates under mild condition with high selectivity is a desired goal in the field of energy and chemistry. But it still remains a great challenge due to the intrinsic inertness of methane originating from strong C-H bonds (104 kcal/mol), low solubility in the solvent, and poor selectivity. Herein, we present a direct single-step conversion of methane to formic acid (HCOOH) using molecular oxygen (O2) as the oxidant under gentle conditions on a decatungstate-doped porous cerium metal-organic framework (Ce-MOF), W10@Ce-bpdc. The HCOOH yield of W10@Ce-bpdc-2 was 155 μmol/gcat at room temperature in 12 h. The process and mechanism of conversion of methane to HCOOH was revealed by spectroscopic characteristics and controlled experiments. In the presence of light, O2 was converted to H2O2 by catalyst and then to ·OH radicals in solution, which interact with methane and undergo intermediates to produce HCOOH. Our experiment provides a new way to catalyze methane in combination with MOF and polyoxometalates (POMs).