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

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.

Graphene Oxide/Fe2O3 Nanocomposite as an Efficient Catalyst for Thermal Decomposition of Ammonium Perchlorate via the Vacuum-Freeze-Drying Method

“…The adsorption calculations were performed using the Vienna ab initio simulation package (VASP) based on the first-principles method of density functional theory (DFT) . The projector-augmented wave (PAW) pseudopotentials with the Perdew–Burke–Ernzerhof (PBE) exchange correlation function were used in the simulation. , A cutoff energy of 450 eV was adopted in the expansion of the plane wave basis set . The Brillouin zone integration was set within the Monkhorst–Pack scheme using the 5 × 5 × 1 k points for geometry optimization and electronic structure calculations .…”

Functionalized ceria–niobium supported nickel catalysts for gas phase semi-hydrogenation of phenylacetylene to styrene

“…59 The adsorbed oxygen has a low coordination value and originates from the active oxygen species (O 2− and O − ) weakly adsorbed on the surface oxygen vacancies. 61 Fig. 4d shows the Nb 3d state of Ni-5% NbCe.…”

Structure–Activity Relationship of Ni-Based Catalysts toward CO2 Methanation: Recent Advances and Future Perspectives

“…The catalyst obtained nearly 95% CH 4 selectivity and keep over 100 h without loss of performance. Besides CNTs, Hashimoto et al fabricated a CeO 2 nanorod with a higher concentration of surface oxygen vacancies and exposed more (110) and (100) planes than a nanocube and nano-octahedron, which are crucial for CO 2 absorption and activation as a result of the abundant active oxygen vacancies (Figure b).…”

“…(b) CO 2 temperature-programmed desorption (TPD) data for NiCeO 2 with different morphologies. This panel was reproduced with permission from ref . Copyright 2021 American Chemical Society.…”

“…As depicted in Figure 6a, 101 the NCNTs can bond well with nickel nanoparticles. The 103 and exposed more ( 110) and ( 100) planes than a nanocube and nanooctahedron, which are crucial for CO 2 absorption and activation as a result of the abundant active oxygen vacancies (Figure 6b). Two-dimensional (2D) materials also obtain considerable interest in CO 2 methanation.…”