Aqueous Au-Pd colloids catalyze selective CH4 oxidation to CH3OH with O2 under mild conditions
Nishtha Agarwal1,Simon J. Freakley1,Rebecca U. McVicker1,Sultan M. Althahban2,Nikolaos Dimitratos1,Qian He1,David J. Morgan1,Robert L. Jenkins1David J. Willock1,Stuart H. Taylor1,Christopher J. Kiely1,2Graham J. Hutchings1,
1Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.2Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015, USA.
http://science.sciencemag.org/content/early/2017/09/06/science.aan6515
Abstract
The
selective oxidation of methane, the primary component of natural gas,
remains an important challenge in catalysis. Using colloidal
gold-palladium nanoparticles rather than the same nanoparticles
supported on titanium oxide, we oxidized methane to methanol with high
selectivity (92%) in aqueous solution at mild temperatures. Using
isotopically labeled O2 as an oxidant in the presence of H2O2, we demonstrate that the methanol produced incorporated a substantial fraction (70%) of gas-phase O2. More oxygenated products were formed than H2O2 consumed, suggesting that the controlled breakdown of H2O2
activates methane which subsequently incorporates molecular oxygen
through a radical process. If a source of methyl radicals can be
established, then the selective oxidation of methane to methanol using
molecular oxygen is possible.
1Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.2Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015, USA.
Abstract
The
selective oxidation of methane, the primary component of natural gas,
remains an important challenge in catalysis. Using colloidal
gold-palladium nanoparticles rather than the same nanoparticles
supported on titanium oxide, we oxidized methane to methanol with high
selectivity (92%) in aqueous solution at mild temperatures. Using
isotopically labeled O2 as an oxidant in the presence of H2O2, we demonstrate that the methanol produced incorporated a substantial fraction (70%) of gas-phase O2. More oxygenated products were formed than H2O2 consumed, suggesting that the controlled breakdown of H2O2
activates methane which subsequently incorporates molecular oxygen
through a radical process. If a source of methyl radicals can be
established, then the selective oxidation of methane to methanol using
molecular oxygen is possible.
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