Nickel nanoparticles with interfacial confinement mimic noble metal catalyst in methane dry reforming

Abstract

In Ni-catalyzed methane dry reforming (DRM), CH4 tends to dissociate directly to form carbon on Ni nanoparticles. The lack of oxygen availability on the Ni surface easily lead to carbon deposition. Here the precise decoration of Ni surface by SiO2 can destroy large Ni ensembles, and meanwhile form metastable Ni − O···Si centers. CH4 activates on the small fraction of Ni to form CHx rather than carbon, the same as that on Rh/SiO2. Moreover, the Ni − O···Si center stabilized by interfacial confinement provide labile oxygen to oxidize CHx. This Ni catalyst exhibits highly stable activity under 650 °C, CH4:CO2 = 2:1 and 5 bars without carbon deposition for 100 h, where carbon formation is thermodynamically much favorable. This study shows inert SiO2 can significantly alter the electronic properties of Ni particles via interfacial confinement, mimicking noble metal catalyst during DRM process.