Methane oxidation using Au/MgO catalysts

A series of Au/MgO(0.04-15 wt%) catalysts have been investigated for the oxidation of methane. Detailed electron microscopy and Mössbauer spectroscopy studies show that two distinct Au morphologies can be observed: (a) two-dimensional Au rafts and (b) discrete three-dimensional Au particles (5-10 nm in diameter). The two-dimensional rafts are observed as the main form of Au at low loadings and, interestingly, these are observed to poison the methane coupling activity of MgO. As the Au loading is increased the proportion of Au present as discrete particles increases and these are considered to be active for methane oxidation to CO and CO2.