Hierarchical Bimodal Mesoporous Structure Modified with Ni Nanoparticles through One-Pot Process for Effective Carbon Dioxide Methanation

Abstract

Abstract With the intent of preparing a catalyst support, a hierarchical bimodal mesoporous structure with two types of mesopores (2–50 nm) that would show both high mass transport and high reaction rate was fabricated through a one-pot process using organic monoliths and surfactant micelles. The selectivity and efficiency of a prototypical carbon dioxide (CO2) reduction reaction, namely, the methanation of CO2 on Ni nanoparticles, were increased by the fabricated structure. This catalytic phenomena was discussed using field-emission scanning electron microscopy (FE-SEM), high-angle annular dark-field imaging scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), N2 adsorption–desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled optical emission spectrometry (ICP-OES), to observe surface area of the structures, catalyst amount, molecular diffusion efficiency, and CO2 methanation mechanisms. The thermal stability of this hierarchical porous structure in the 823–1273 K temperature range was also examined. Although additional experiments such as the change of the pore size, pore shapes, and the ratio of the larger pores and smaller pores, are required to further discussions, there is a possibility that the hierarchical bimodal mesoporous structure can be a good catalyst support.