Embedding uniform Ni nanoparticles into Silicalite-1 zeolite for dry reforming of methane

Abstract

Embedding Ni nanoparticles (NPs) into support is a highly efficient dry reforming of methane (DRM) catalyst. However, the large Ni particle size and uneven distribution result in metal sintering and catalyst deactivation. Herein, using nanosized MFI zeolites silicalite-1 (S-1) as support, the Ni@S-1 zeolite catalyst with highly dispersed Ni NPs was synthesized by ethanol-assisted impregnation method. The Ni NPs with small size (1.5 nm) are uniformly encapsulated in S-1 zeolite, and they slightly increase to 2.5 nm after DRM reaction but remain well dispersed. Compared with Ni/S-1 catalyst prepared by deposition precipitation, the sizes of Ni NPs in Ni@S-1 maintain smaller and present more uniform dispersion. The strong metal–support interaction between encapsulated Ni species and S-1 zeolite endowed Ni@S-1 catalyst high sintering- and coking-resistant properties in the dry reforming of methane. The CH4 and CO2 conversions over Ni@S-1 catalyst can still reach 89% and 94% after 200 h, respectively, which are superior than most reported Ni-based zeolite catalysts and other Ni-based catalysts. This work provides guidance for the synthesis of Ni-based zeolite catalysts with high performance.