CO2 Methanation over Rare Earth Doped Ni-Based Mesoporous Ce0.8Zr0.2O2 with Enhanced Low-Temperature Activity

Zhenglong Yang,Mindong Chen,Leilei Xu,Pengxiang Ge,Yan Cui

doi:10.3390/catal11040463

Zhenglong Yang, Mindong Chen + Show 3 more

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https://doi.org/10.3390/catal11040463

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Abstract

The Ni-based catalysts have a wide range of industrial applications due to its low cost, but its activity of CO2 methanation is not comparable to that of precious metal catalysts. In order to solve this problem, Ni-based mesoporous Ce0.8Zr0.2O2 solid solution catalysts doped with rare earth were prepared by the incipient impregnation method and directly used as catalysts for the methanation of CO2. The catalysts were characterized systematically by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2-TPR), CO2 temperature programmed desorption (CO2-TPD), and so on. The results show that Ni is highly dispersed in the mesoporous skeleton, forming a strong metal-skeleton interaction. Therefore, under the condition of CO2 methanation, the hot sintering of metallic Ni nanoparticles can be effectively inhibited so that these mesoporous catalysts have good stability without obvious deactivation. The rare earth doping can significantly increase the surface alkalinity of catalyst and enhance the chemisorption of CO2. In addition, the rare earth elements also act as electron modifiers to help activate CO2 molecules. Therefore, the rare earth doped Ni-based mesoporous Ce0.8Zr0.2O2 solid solution catalysts are expected to be an efficient catalyst for the methanation of CO2 at low-temperature.

Highlights

In the past hundred years, with the growth of the world population and the development of the global economy, CO2 emissions from the burning of fossil fuels have been on the rise [1,2]
The absence of the ZrO2 diffraction peak indicated that ZrO2 was successfully integrated into the CeO2 lattice to form a solid solution while maintaining the crystal structure of fluorite [39]
The NiO diffraction peak of the 15Ni2La/M-Ce80Zr20 catalyst was the weakest, which indicated that the doping of rare earth La was most conducive to the dispersion of NiO

Summary

Introduction

In the past hundred years, with the growth of the world population and the development of the global economy, CO2 emissions from the burning of fossil fuels have been on the rise [1,2]. The massive emissions of CO2 have led to many environmental problems such as global warming, sea level rise, polar ice melting and so on [3]. (g) → CH4 (g) + 2H2 O (g), ∆H298K = −165.4 kJ/mol, ∆G298K = −130.8 kJ/mol) in 1897 [5]. This reaction can realize the utilization of CO2 resources, and has potential economic and environmental value, which is a widely studied topic [7]. Hashimoto et al [4]

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