Catalytic conversion of high-GWP gases N2O and CH4 to syngas (H2 + CO) on SiO2@Ni-Cr layered nano-oxide-coated monolithic catalyst

Saikia, Pinky; Gogoi, Champa; Kalita, Paran Jyoti; Lochan Goswamee, Rajib

Catalytic conversion of high-GWP gases N2O and CH4 to syngas (H2 + CO) on SiO2@Ni-Cr layered nano-oxide-coated monolithic catalyst

2020

Saikia, Pinky | Gogoi, Champa | Kalita, Paran Jyoti | Lochan Goswamee, Rajib

Layered double hydroxides (LDHs) are 2D nano-sheets where different M²⁺ and M³⁺ metal cations are uniformly distributed in Mg(OH)₂ brucite-like sheets and various charge-compensating anions (Aⁿ⁻) are present in their interlayer spaces. This work includes preparation of different SiO₂@Ni/Cr mixed-metal layered nano-oxide-type catalysts by the calcination of SiO₂@Ni-Cr LDH nano-composite–based alcogel coated over a honeycomb monolithic substrate and their use as a catalytic device for the study of catalytic partial oxidation (CPO) of CH₄ both in the presence of O₂ and in the presence of N₂O under atmospheric pressure at different temperatures not exceeding 500 °C to study the effect of N₂O on the CPO of CH₄. It was observed that in the presence of O₂ the yield of syngas (H₂ + CO) did not exceed 90% whereas in the presence of N₂O about 99.9% syngas (H₂ + CO) was observed. The selectivity towards syngas production reached a maximum value when an optimal reaction condition was maintained at 1:1 CH₄:N₂O mol ratio with a temperature of 500 °C. XPS analysis showed that a NiO-type compound formed on the decomposition of the LDH component after H₂ treatment was reduced to disperse Ni⁰, which acted as an active catalytic species. Graphical abstract Schematic representation of catalytic partial oxidation of CH₄ in the presence of N₂O by SiO₂@Ni-Cr-LDH-based mixed-metal nano-oxide.

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