Pivotal Role of Ni/ZrO2 Phase Boundaries for Coke-Resistant Methane Dry Reforming Catalysts

To identify the synergistic action of differently prepared Ni-ZrO2 phase boundaries in methane dry reforming, we compared an “inverse” near-surface intermetallic NiZr catalyst precursor with respective bulk-intermetallic NixZry material and a supported catalyst. In all three cases, stable high reforming activity enhanced anticoking properties can be assigned to presence extended boundaries, which result from situ activation Ni-Zr model systems under DRM conditions. All catalysts operate bifunctionally; is essentially decomposed carbon at metallic Ni0 surface sites, whereas CO2 reacts CO reduced Zr centers induced by spillover boundaries. On pure bulk Ni0, dissolved accumulates surface-near regions, leading sufficiently supersaturated state for completely surface-blocking graphitic segregation. strong contrast, surface-ZrO2 modified exhibits virtually best decoking conversion conditions due highly dispersed ZrO2 islands particularly large contribution interfacial Ni0-ZrO2 sites short C-diffusion pathways latter.