Iridium single-atoms induced in situ H2O2 formation boosting the hydrothermal oxidation of methane to methanol with molecular O2

Partial oxidation of methane to methanol has become a heavily investigated field. For cases using O2 as oxidant, overoxidation is undesired and inevitable. To address this issue, we construct a single atom Ir1/C catalyst with a unitary active site to achieve a high selectivity of methanol. Here we employed the O-adsorption modulation strategy to control the O2 dissociation path on Ir site, where O2 transforms into H2O2 on Ir single atoms (SAs) in contrast to Ir-O on Ir clusters. The subsequent decomposition of H2O2 into H2O and *O on Ir SAs vastly decreases the barriers of CH4 oxidation process, compared to the Ir clusters. Operando infrared spectroscopy demonstrates the observation of Ir-OOH, a strong evidence for the distinguished intermediate of Ir-HOOH. H2O2 was also detected and quantified as another important evidence for the formation of Ir-HOOH. Ir1/C exhibited a much higher methanol productivity of 17mmol g- 1 than Ircluster/C (6mmol g- 1) under a feeding of 0.3 MPa CH4 and 0.1 MPa air in water at 150 degrees C for 3 h, and the value raised to 31.3mmol g- 1 under 0.3 MPa CH4. This work demonstrates that selectivity control and activity promotion in O-involved reaction can be realized via the Oadsorption modulation strategy.