MAl2O4 (M: Mg, Ni, and Co) as unique support for Ni active metal to form a catalyst for renewable biohydrogen and syngas production from glycerol reforming over a microchannel reactor. (15th January 2023) - Khani, Yasin
Graphical abstract: Highlights: Ni/NiAl2 O4 has the most glycerol conversion in GSR (97.4%) and GDR processes (98.7%) at high reaction temperatures among Ni/MAl2 O4 (M: Mg, Ni, Co) catalysts. The H2 /CO ∼ 1 was achieved for NiO/NiAl2 O4 catalyst in GDR. Amount of coke formation after 32 h on stream was highest for Ni/CoAl2 O4 catalyst in GDR process. Abstract: Different mesoporous aluminate MAl2 O4 spinels (with M: Mg, Ni, and Co) were fabricated via a sol–gel procedure. The fabricated spinels each were then used as support for a Ni active metal to synthesize a catalyst, and the performance of the spinel as part of the catalyst used in glycerol steam reforming (GSR) and dry reforming (GDR), respectively, was investigated. Further, the catalysts were characterized using XRD, EDX-Mapping, H2 -TPR, TEM, NH3 -TPD, and SBET analyses, respectively. Notably, the catalysts each displayed a high BET specific surface area in the range of 130–190 m 2 /g. In addition, hydrogen production by GSR and GDR under different synthesized catalysts was evaluated in the temperature ranges of 500–700 °C and 600–800 °C, respectively, in a monolithic reactor. In particular, a high glycerol conversion, H2 yield, and CO selectivity, and low CO2 selectivity were achieved using the NiO/NiAl2 O4 catalyst in GSR. Further, the order of catalytic performances with regard to glycerol conversion, H2 yield, and CO selectivity was the catalytic performance of NiO/NiAl2 O4 > NiO/MgAl2 O4 > NiO/CoAl2 O4, respectively. Likewise, the H2 /CO ratio in the temperature range of 600–800 °C was closest to ∼ 1 in the case of the NiO/NiAl2 O4 catalyst used in GDR. Subsequent TGA analysis of each spent catalyst after 32 h of use showed that the amount of coke production in GDR was much higher than that in GSR. In addition, the highest amount of coke deposition was with the use of the NiO/CoAl2 O4 catalyst in these reformings.