Small-sized Ni nanoparticles embedded nickel phyllosilicate as a metal-acid bifunctional zeolite catalyst for cooperatively boosting CO2-CH4 reforming

Ni-based catalysts using siliceous materials as the supports have suffered from two challenging issues of sintering and carbon deposition for dry reforming of methane (DRM), resulted from a weak metal-support interaction. Given these, a novel metal-acid bifunctional Ni@S-1 zeolite catalyst is tailored from the evolution of hydroxylated nickel phyllosilicates that are formed by subtly controlling the coordination environments of Ni precursor complexes in the silicalite-1 (S-1) zeolite. The developed Ni0.44@S-1 catalyst renders almost equivalent CH4 and CO2 conversions (85.1 % and 88.7 %), high H-2/CO molar ratio (about 1) and superb long-term stability during 100 h with no activity loss at 750 degrees C with a WHSV of 100 L.g(cat)(-1).h(-1), outperforming other control catalysts under investigation. Such superior catalytic behavior benefits from the synergy between highly uniform Ni nanoparticles (3-5 nm) confined in the micropores of zeolite and substantially formed Lewis acid sites due to coordinatively unsaturated Ni2+ sites located at the reduced 2:1 nickel phyllosilicate, as revealed by detailed characterizations. Meanwhile, it further discloses that a benign balance between formation and elimination of "process carbon" species is responsible for improving the carbon resistance of catalyst during the DRM reaction. The present design broadens a new insight for the development of new Ni-based catalysts with simultaneous coking- and sintering-resistant for the DRM application.