Mechanism and Kinetics of Methane Oxidation to Methanol Catalyzed by AuPd Nanocatalysts at Low Temperature

Abstract

The selective oxidation of methane to methanol at ambient conditions has the potential to enable the use of natural gas obtained in remote areas. We performed multivariate statistical analysis of 137 laboratory experiments to show that gold–palladium nanocatalysts unlock the reaction pathway that forms methanol, but the overall rate of methane oxidation does not correlate with the total number of active sites because the catalyst does not participate in the rate limiting step of the reaction. Using an H2O2 concentration below 2.5 × 10–5 mol/L reduces the H2O2 overuse up to 10,000 times and promotes a methanol selectivity greater than 0.8 without compromising the reaction productivity. These results have enormous practical importance for methane utilization because they explain the poor methane conversion rates obtained thus far and show the path to increase the methanol productivity and reduce the overuse of industrially expensive H2O2.