How the Morphology of NiO x-Decorated CeO2 Nanostructures Affects Catalytic Properties in CO2 Methanation

Naoki Hashimoto; Kohsuke Mori; Kohei Asahara; Shun Shibata; Hirotaka Jida; Yasutaka Kuwahara; Hiromi Yamashita

doi:10.1021/acs.langmuir.1c00546

How the Morphology of NiO _x-Decorated CeO₂ Nanostructures Affects Catalytic Properties in CO₂ Methanation

Langmuir. 2021 May 4;37(17):5376-5384. doi: 10.1021/acs.langmuir.1c00546. Epub 2021 Apr 21.

Authors

Naoki Hashimoto¹, Kohsuke Mori^{1

2

3}, Kohei Asahara¹, Shun Shibata¹, Hirotaka Jida¹, Yasutaka Kuwahara^{1

2

3

4}, Hiromi Yamashita^{1

2

3}

Affiliations

¹ Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
² Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan.
³ Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan.
⁴ JST, PRESTO, Kawaguchi, Saitama 332-0012, Japan.

PMID: 33881888
DOI: 10.1021/acs.langmuir.1c00546

Abstract

Effects of morphology and exposed crystal planes of NiO_x-decorated CeO₂ (NiCeO₂) nanostructured catalysts on activity during CO₂ methanation were examined, using nanorod (NR), nanocube (NC), and nanooctahedron (NO) structures. The NiCeO₂ nanorods (NiCeO₂-NR) showed superior activity to NiCeO₂-NC and NiCeO₂-NO along with excellent selectivity for CH₄. This material also demonstrated exceptional durability, with no significant loss of catalytic activity or structural change after use. Comprehensive physicochemical characterization as well as density functional theory calculations determined that the high performance of the NiCeO₂-NR was closely related to the large quantity of surface oxygen vacancies and the high degree of reversibility associated with the Ce⁴⁺ ↔ Ce³⁺ redox cycle of the support. These effects originate from the enhanced reactivity of oxygen atoms on the (110) surfaces of the oxide compared with the (100) and (111) surfaces. This information is expected to assist in the rational design of practical catalysts for the activation of CO₂ molecules and other important transformations.