(406d) A Multicore-Shell Catalyst Derived from Ni Phyllosilicate@SiO2 for Low Temperature Dry Reforming of Methane: Confinement Effect Against Carbon Formation

Dry reforming of methane has been a popular research topic since it converts two “green” gases into syngas (CO+H2). The main issue for Ni-based catalysts is the severe carbon formation which covers active sites, leading to deactivation. A lot of effort has been put to get stable Ni catalysts with less carbon formation, in which confinement effect has been proven to be a good strategy.

In this report, we manage to synthesize a novel multicore-shell catalyst. Firstly, Ni phyllosilicate is supported on silica nanospheres with ammonia evaporation method. Then Ni phylloslicate nanospheres are coated with a layer of mesoporous SiO2 to obtain a core-shell structure of Ni phyllosilicate@SiO2 via hydrolysis of TEOS. The thickness of shell can be tuned via varying the amount of TOES. After H2 reduction at high temperature, multiple small Ni nanoparticles (~3nm) are formed supported on the inner SiO2 core but also encapsulated within the outer mesoporous SiO2 shell.

This multicore-shell catalyst shows a high and stable conversion (~60%, GHSV=60,000ml/h g_cat) along 24h time of stream (TOS) at 600°C while the pristine Ni phyllosilicate suffers from heavy carbon formation and the reactor is blocked after 3h TOS. TGA and TEM of spent catalysts have shown that there is almost no carbon formation for this novel multicore-shell catalyst.

Compared with conventional Ni@SiO2 core-shell catalyst, our multicore-shell catalyst is much easier to synthesize and does not need any toxic organic solvent. And low reaction temperature (600°C) also helps to reduce the energy input. We believe this strategy of making multicore-shell catalyst can be extended and may be helpful to researchers in the same field.