Support effect in Ni-based catalysts for methane steam reforming: Role of MxOy-Al2O3 (M = Ni, Mg, Co) supports for enhanced catalyst stability
Yi Lin, Zaixing Wang, Lina Tang, Jiang Shi, Yu Guo, Xiao‐Qin Liu
Abstract
Ni-based catalysts supported on composite metal oxides (NiO-Al 2 O 3 , MgO-Al 2 O 3 , Co 3 O 4 -Al 2 O 3 ) were synthesized via coprecipitation followed by Ni impregnation to investigate the influence of support composition on catalyst stability in methane steam reforming. Accelerated deactivation protocols (methane decomposition, high-temperature sintering, hydrothermal oxidation) revealed hydrothermal oxidation as the primary cause of irreversible deactivation. The 10Ni/NiAl catalyst (10 wt% Ni/10 wt% NiO-Al 2 O 3 ) showed remarkable regenerability after 923 K hydrothermal treatment, fully restoring its activity. This was attributed to coexisting reduced Ni species and readily reducible NiO, facilitating rapid reactivation. Other catalysts formed thermally stable NiAl 2 O 4 , leading to permanent deactivation. Methane cracking at 973 K had negligible effect, and 10Ni/NiAl catalyst exhibited the lowest carbon deposition (17.02 %). Under extreme hydrogen purged at 1223 K, only the 10Ni/CoAl catalyst exhibited a minor activity decline. The superior stability of 10Ni/NiAl was attributed to an in situ-formed NiAl composite metal oxides during 973 K calcination, which effectively anchored Ni particles, suppressed sintering, and prevented extensive oxidation. • The stability of Ni-based catalysts is significantly influenced by composite metal oxide supports. • Hydrothermal oxidation is the primary cause of catalyst deactivation. • 10Ni/CoAl catalyst is the most affected by forced sintering at 1223 K • 10Ni/NiAl catalyst shows exceptional activity and stability for 300 h in methane steam reforming. • 10Ni/NiAl catalyst recovers its activity after multiple start-up/shut-down cycles without inert gas protection.