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 coconvert two greenhouse gases (CO 2 and CH 4 ) into syngas (CO and H 2 ), requiring a robust catalyst for extensive application. CeO 2 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 CeO 2 support (namely, Ni/CeO 2 -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 CH 4 and CO 2 conversions could reach 83.94 and 82.81% at 800 °C, respectively. Meanwhile, the Ni/CeO 2 -H catalysts are thoroughly characterized using X-ray diffraction, N 2 adsorption− desorption, scanning electron microscopy, H 2 temperature-programmed reduction, CO 2 temperature-programmed desorption, X-ray photoelectron spectroscopy, thermogravimetric analysis, and CO 2 temperature-programmed oxidation (CO 2 -TPO), and the results demonstrate the enhancing effect of spatial confinement for the honeycomb-lantern-like structure. Moreover, the kinetics studies reveal that Ni/CeO 2 -H has the lowest activation energy (97.61 kJ/mol) among these Ni/CeO 2 catalyst samples, which can facilitate its excellent catalytic performance effectively. Based on the semiempirical power rate equation, the reaction orders of CH 4 and CO 2 for Ni/CeO 2 -H are 0.60 and 0.17, respectively. Furthermore, the activation energy of coke gasification for the spent Ni/CeO 2 -H catalyst is investigated and determined by the CO 2 -TPO technique on the basis of extrapolating the Wigner−Polanyi equation.

Confinement effects over Ni-based catalysts for methane dry reforming

“…The honeycomb cerium oxide (CeO 2 -H)-loaded nickel species were shown to realize the spatial confinement of nickel particles. 78 Ni/ CeO 2 -H catalyst was obtained by a solvothermal method, where the active Ni nanoparticles were grown on the surface of the support, as shown in Fig. 5a.…”