Abstract
Recent technological advances turned feasible the synthesis of catalysts with their active phase atomically dispersed. CuMgAl hydrotalcite-derived mixed-oxide supported NiCu catalysts were prepared by the modified galvanic replacement, with 8% Cu and Ni/Cu molar ratio of 0.1, 0.01, 0.002, and 0.001. The catalysts were characterized by EDS, XRD, TGA, TPR, H2 chemisorption, TPD-CO2, DRIFTS, and SEM. DRIFTS and H2 chemisorption indicated the presence of Ni atomic species in Ni0.002Cu/CuMgAl and Ni0.001Cu/CuMgAl catalysts. All catalysts were tested in the dry reforming of methane at 800 °C and 100 mL min−1 (1:1:0.5 CH4:CO2:N2). Ni0.1Cu/CuMgAl presented the highest activity, with a 39% CH4 conversion and 143 s−1 TOF. The catalysts presented a significant deactivation further investigated by TGA, SEM, and Raman spectroscopy. Over 1.0 mgC/mgcat was deposited in every catalyst except Ni0.1Cu/CuMgAl. A higher formation of amorphous carbon was observed. The difference in carbon species could be evaluated. Cu sintering was also observed.
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