Syngas production by the CO2 reforming of CH4 over Ni–Co–Mg–Al catalysts obtained from hydrotalcite precursors

The catalytic performance of the Ni, Co, Mg, and Al mixed-oxide solids, synthesized via hydrotalcite route, was investigated towards the dry reforming of methane for hydrogen production. The hydrotalcite structure was successfully obtained upon the synthesis. After calcination at 800 °C under an air flow, this structure was completely decomposed and the resulting oxides (Co_xNi_yMg_zAl₂800, x and y = 0; 1; 2; 3; 4, z = 2; 4, x + y + z = 6, x, y, and z are the molar ratios) were used as catalysts and were characterized using X-ray diffraction and Temperature-Programmed Reduction. The dry reforming of methane was carried out using a mixture of CH₄:CO₂ (1:1) after 2 h of reduction under an H₂ flow at 800 °C. Co₂Ni₂Mg₂Al₂800 showed the highest catalytic activity in the studied series, ascribable to an interaction between Ni and Co, which is optimal for such Co/Ni ratio. The post-reaction characterization of the catalytic samples by X-ray diffraction and Differential Scanning Calorimetry evidenced a better resistance towards carbon deposition for the catalysts where Co molar ratio is higher than Ni.