Excess-methane dry and oxidative reforming on Ni-containing hydrotalcite-derived catalysts for biogas upgrading into synthesis gas

The activity of Ni-containing hydrotalcite-derived catalysts was assayed in the excess-methane dry reforming of different CH4-CO2 mixtures, aiming to simulate biogas upgrading to hydrogen and/or syngas. These catalysts yielded methane conversions quite far away from the thermodynamically predicted values, pointing to the inhibition of important methane consuming reactions, such as direct methane decomposition (DMD). Adding oxygen to the gas mixture (12.5%) results in increased methane conversions. Almost constant H2/CO ratios, around 1.5, were measured at any temperature (600-850 °C). However, solid carbon formation was found to take place to a higher extent. The intrinsic properties of the hydrotalcite-derived catalysts tested results in favored reverse water gas shift reaction, leading to CO2 and H2 conversion.