Bi-reforming of methane with carbon dioxide and steam on nickel-supported binary Mg-Al metal oxide catalysts

Bi-reforming of methane (CH₄) with carbon dioxide (CO₂) and steam is a promising process to produce syngas with a H₂/CO ratio of about 2, which can be directly used as a feedstock for methanol synthesis. This work studied nickel nanoparticles supported on the binary Mg-Al metal oxide catalysts for the bireforming of CH₄. The XRD, TEM, and FT-IR results confirm the successful synthesis of Ni/MgO, Ni/Mg_xAl_yO, and Ni/Al₂O₃ catalysts. The TPR profile shows that the reduction temperature of Ni species was slightly decreased upon addition of Al due to the formation of the NiAl₂O₄ phase. The XPS spectra demonstrate that Ni/MgO and Ni/Al₂O₃ exhibit higher amounts of Ni⁰ after H₂ reduction. It can explain the origin of the superior catalytic performance of Ni/MgO and Ni/Al₂O₃ over the Ni/Mg_xAl_yO catalysts possessing less Ni⁰ species during the H₂ reduction process. Compared to the conventional dry reforming of CH₄, the bi-reforming process features a higher CH₄ conversion and a H₂/CO ratio close to 2, which is suitable for methanol synthesis without further separation and adjustment steps.