Bi-functional CeO2 coated NiCo-MgAl core-shell catalyst with high activity and resistance to coke and H2S poisoning in methane dry reforming

A bi-functional core-shell catalyst is reported for CO2 reforming of methane, that combines high catalytic activity with resistance to both coke formation and deactivation by H2S poisoning. We developed a NiCo-MgAl@CeO2 core-shell catalyst incorporating a layered double hydroxide-derived core and a CeO2 shell that shows high DRM activity and stability and enhanced resistance to H2S-induced deactivation, while maintaining negligible coke formation through the steric confinement effect of the core-shell morphology and the participation of lattice oxygen of CeO2 in coke oxidation. Co addition in the core delays the onset of catalyst deactivation in the presence of H2S by altering sulfur chemisorption kinetics, and the lattice oxygen of the CeO2 shell suppresses steady-state catalyst deactivation under continuous H2S flow by oxidatively removing H2S under continuous replenishment by CO2. The synergistic and complementary properties of the NiCo-containing core and CeO2 shell results in simultaneous coke resistance and H2S tolerance of the bi-functional catalyst.