(159z) Engineering Oxygen Vacancies at Metal-Oxide Interface By Depositing Ultra-Thin ZrO2 Overcoating on Ni/Al2O3 for Dry Reforming of Methane

ZrO₂ overcoating was deposited onto Ni/Al₂O₃ catalyst by atomic layer deposition (ALD) for dry reforming of methane (DRM). H₂-reduction of the catalyst could transform as-prepared ZrO₂ thin films to tetragonal phase, thus cracking the ZrO₂ overcoating. The ZrO₂ overcoating could be partially reduced by H₂ in the presence of Ni and the formation of interfacial oxygen vacancies could be induced. During DRM, the oxygen vacancy at Ni-ZrO₂ interface can enhance the CO₂ activation by dissociating CO₂ and releasing active O, thereby limiting the growth of carbon intermediates and decreasing the carbon deposition. For DRM at 800 °C and 700 °C, the Ni/Al₂O₃ overcoated with 5 cycles of ZrO₂ ALD showed the highest activity and stability. For DRM at 600 °C, no deactivation was observed for the Ni/Al₂O₃ overcoated with 10 cycles of ZrO₂ ALD during 100 h test, as compared to 56% relative activity loss of pristine Ni/Al₂O₃. In summary, constructing Ni-ZrO₂ interface with oxygen vacancies by ZrO₂ ALD can effectively improve the activity and stability of Ni/Al₂O₃ catalyst for DRM.