Ceria–gadolinia supported NiCu catalyst: A suitable system for dry reforming of biogas to feed a solid oxide fuel cell (SOFC)

NiCu/Ce0.9Gd0.1O2−δ (CGO) catalysts were prepared by different techniques with the aim to develop a bifunctional catalyst, characterized both by catalytic and anodic properties for integrated biogas SOFC process. Catalytic measurements have been performed in CO2 reforming of CH4, using a fixed bed reactor at a reaction temperature ranging from 650 to 800 °C. Results revealed that NiCu/CGO system is a promising catalyst for the conversion of biogas mixtures at temperature suitable to be used in low temperature solid oxide fuel cell (LT-SOFC). Characterization data clearly demonstrated that NiCu alloy forms by reduction of NiCuOx mixed oxide patches, while catalytic testing showed carbon-free operation at 800 °C (GHSV = 6600 h−1) when “CO2-rich” biogas mixtures are used. By a thermodynamic evaluation of the different reaction kinetics, the poor efficiency of the catalyst in promoting the carbon gasification by CO2 reaction has been assessed. Characterization of spent catalysts shed light both on the reasons of deactivation phenomena occurring with time over the catalysts and on the deactivation kinetics under the adopted experimental conditions.

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► Design an efficient system suitable for dry reforming of a simulated biogas mixture.
► The formation of a nickel–copper solid solution results to be fundamental.
► Copper addition promotes the kinetics of nickel reduction.
► The decay kinetics is fundamentally ruled out by the coking rate.
► By feeding CO2-lean biogas mixtures, carbon considerably forms also at 800 °C.