Catalytic conversion of high-GWP gases N2O and CH4 to syngas (H-2 + CO) on SiO2@Ni-Cr layered nano-oxide-coated monolithic catalyst

摘要

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 (A(n-)) 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 O-2 and in the presence of N2O under atmospheric pressure at different temperatures not exceeding 500 degrees C to study the effect of N2O on the CPO of CH4. It was observed that in the presence of O-2 the yield of syngas (H-2 + CO) did not exceed 90% whereas in the presence of N2O about 99.9% syngas (H-2 + 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 degrees C. XPS analysis showed that a NiO-type compound formed on the decomposition of the LDH component after H-2 treatment was reduced to disperse Ni-,(0) which acted as an active catalytic species.