Geometric design of a Ni@silica nano-capsule catalyst with superb methane dry reforming stability: enhanced confinement effect over the nickel site anchoring inside a capsule shell with an appropriate inner cavity†
Abstract
Catalyst deactivation via severe carbon deposition and metal sintering is a significant obstacle to the industrialization of CO2 reforming of methane (CRM). Previous reports are mainly focused on metal oxide supported catalysts, which were proved to be less effective in eliminating the formation of carbon deposition completely. Here, we report a facile strategy for the preparation of a highly dispersed Ni@SiO2 nano-capsule catalyst, which features a monodisperse capsule and anchored Ni NPs in the inner porous shell. By virtue of this, carbon formation could be sterically hindered due to the sealed space for carbon formation and growth, and therefore excellent catalytic performance was achieved. Through comprehensive characterization and comparison of traditional supported catalysts as well as capsule catalysts with different architectures, the importance of a confined capsule structure in preventing carbon formation was convincingly demonstrated. Our work disclosed a morphological approach that is much more effective in preventing sintering of Ni NPs and suppressing carbon formation simultaneously, therefore shedding new light on the design and preparation of highly stable Ni-based catalysts for reforming reactions.