Ni Supported on Hollow CeO2 Microspheres with Controllable Shell Thickness for Catalytic Dry Reforming of Methane

CeO2 hollow nanospheres were fabricated through a hard template-assisted route, with the shell thickness precisely tuned by varying the usage amount of Ce(NO3)3·6H2O. Ni was subsequently deposited onto the xCeO2-H (x = 6, 8, 10) supports via an incipient wetness impregnation method, affording Ni/6CeO2-H, Ni/8CeO2-H, and Ni/10CeO2-H catalysts, which were evaluated for catalytic dry reforming of methane (DRM). Notably, the Ni/6CeO2-H catalyst delivered stable CH4 and CO2 conversions of 70% and 76%, respectively, with an H2/CO molar ratio of 0.81 over a reaction period of 50 h at 750 °C, demonstrating exceptional catalytic stability. Comprehensive characterization revealed that the Ni/6CeO2-H catalyst featured stronger metal–support interaction (MSI) and abundant basic sites, which synergistically enhanced CO2 adsorption and activation, thereby endowing the catalyst with superior coke resistance. In situ infrared spectroscopy further elucidated the DRM reaction mechanism, revealing that surface –OH groups played a pivotal role in suppressing coke formation and sustaining high reaction efficiency by reacting with carbon precursor species (CHx*).