Synthesis of the CeO2 Support with a Honeycomb-Lantern-like Structure and Its Application in Dry Reforming of Methane Based on the Surface Spatial Confinement Strategy

Abstract

Dry reforming of methane has received considerable interest as one of the most efficient thermocatalysis routes to co-convert two greenhouse gases (CO2 and CH4) into syngas (CO and H2), requiring a robust catalyst for extensive application. CeO2 with a honeycomb-lantern-like structure is fabricated by a facile template-free solvothermal process, followed by calcination, and the nickel-active component is confined on the surface of the honeycomb-lantern-like CeO2 support (namely, Ni/CeO2-H) and employed in dry reforming of methane. The catalytic performance of the prepared sample is evaluated in a fixed-bed tubular reactor, and the CH4 and CO2 conversions could reach 83.94 and 82.81% at 800 °C, respectively. Meanwhile, the Ni/CeO2-H catalysts are thoroughly characterized using X-ray diffraction, N2 adsorption–desorption, scanning electron microscopy, H2 temperature-programmed reduction, CO2 temperature-programmed desorption, X-ray photoelectron spectroscopy, thermogravimetric analysis, and CO2 temperature-programmed oxidation (CO2-TPO), and the results demonstrate the enhancing effect of spatial confinement for the honeycomb-lantern-like structure. Moreover, the kinetics studies reveal that Ni/CeO2-H has the lowest activation energy (97.61 kJ/mol) among these Ni/CeO2 catalyst samples, which can facilitate its excellent catalytic performance effectively. Based on the semiempirical power rate equation, the reaction orders of CH4 and CO2 for Ni/CeO2-H are 0.60 and 0.17, respectively. Furthermore, the activation energy of coke gasification for the spent Ni/CeO2-H catalyst is investigated and determined by the CO2-TPO technique on the basis of extrapolating the Wigner–Polanyi equation.