Decreasing the oxygen reactivity in catalysts can increase hydrogen production from methane oxidation, claim Chinese scientists. 

The partial oxidation of methane produces syngas (CO/H₂ mixture) and is an attractive alternative to petroleum fuel. But, the process occurs simultaneously with total oxidation of methane which does not produce H₂ directly and also releases heat that forms hot-spots on the catalyst that deactivate or destroy them, explains Guanzhong Lu at East China University of Science and Technology, Shanghai, China. 

Lu and colleagues found that the reactivity of the oxygen atoms in the catalyst determines whether total oxidation or partial oxidation takes place. Adding europium ions into the catalyst structure makes stronger bonds that prevent the oxygen atoms reacting and more hydrogen is produced. 

'We were amazed to find that hydrogen could be produced directly over the europium-doped oxide catalyst,' says Lu. 'This may lead to better utilization of methane; decreasing the cost of natural gas, which could lessen our reliance on petroleum,' he adds. 

Stuart Taylor, an expert in heterogeneous catalysts for selective oxidations at Cardiff University, comments 'The direct formation of hydrogen from methane partial oxidation is desirable, but to achieve high yields, over-oxidation of thermodynamically less stable products must be controlled.' 

Lu adds that the key factors that control the switch from partial to total oxidation are yet to be solved and the group plan to investigate the catalyst design further. 

Carl Saxton 

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