New synthesis strategies for Ni/Al2O3-Sil-1 core–shell catalysts for steam reforming of methane

Abstract

The catalytic performance of Ni/Al2O3-Sil-1 core–shell catalysts was investigated for the steam reforming of methane (SRM). The core–shell catalysts consisting of Ni/Al2O3 core catalyst and silicalite-1 (Sil-1) zeolite shell were prepared by different synthesis routes. Catalyst characterization indicates that repeated calcination at elevated temperatures during the catalyst preparation should be avoided to prevent the formation of the inactive NiAl2O4 spinel phase. Thus, the new preparation procedure for the core–shell catalyst involves first growing a Sil-1 shell on the alumina beads to obtain Al2O3-Sil-1 core–shell beads, followed by an incipient wetness impregnation to obtain a Ni/Al2O3-Sil-1 catalyst. The catalytic activity of the catalyst for the SRM reaction displayed ca. 10% improvement over core–shell catalysts prepared by traditional method. The prepared catalysts maintained high reactivity even when exposed to alkali vapor during reaction.