Synergetic Catalytic Effects in Tri‐Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation

Cui, Xiangzhi; Wang, Yongxia; Chen, Li‐Song; Shi, Jianlin

doi:10.1002/cctc.201402392

Cited by 17 publications

(7 citation statements)

References 74 publications

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“…The properties of ceria, in turn, are associated with the arrangement of the terminated surface oxygen atoms, which greatly depends on the morphology, structure, and components. Generally, there are two strategies to enhance ceria catalytic activity, including the optimization of ceria morphologies/structures and the combination of ceria with secondary species, such as noble metals or metal oxides, to form composites . For the first strategy, numerous morphologies/structures of ceria have been designed, such as nanorods, nanotubes, nanosheaths, nanobundles, mesoporous, cage bells, and other morphologies/structures .…”

Section: Introductionmentioning

confidence: 99%

The Template‐Free Synthesis of CuO@CeO₂ Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

Yuan

Ning

et al. 2018

Eur J Inorg Chem

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The template-free construction of hollow multiporous materials with hierarchically multiporous walls, unique morphologies, and functionalities remains a great challenge in materials science. Here, we describe a facile template-free approach to synthesize hollow multiporous-walled CeO 2 (HMW-CeO 2 ) nanospheres. The HMW-CeO 2 nanosphere possesses a hierarchically multiporous wall, with pore sizes ranging from micropores to mesopores, centered at 0.43, 4.2, and 14.3 nm. The CuO loaded HMW-CeO 2 support (HMW-CuO@CeO 2 ) is eval- [a] Preparation of Ceria Alkoxide Nanospheres: Ceria alkoxide nanospheres were synthesized by mixing Ce(NO 3 ) 3 ·6H 2 O, 2-propanol, and glycerol in a Teflon™-lined stainless-steel autoclave. In a typical synthesis, Ce(NO 3 ) 3 ·6H 2 O (0.868 g) was dissolved in 2-propanol (30 mL) and stirred for 30 min. Glycerol (10 mL) was added to the above solution and stirred for 30 min. The mixture was then transferred into a Teflon™-lined stainless-steel autoclave at 150°C for 8 h. After cooling to room temperature naturally, the precipitate was filtered, washed, and dried at 80°C to obtain ceria alkoxide nanospheres. Preparation of Hollow Multiporous-Walled CeO 2 (HMW-CeO 2 ):HMW-CeO 2 was prepared by the hydrothermal reaction of ceria alkoxide nanospheres. Typically, ceria alkoxide nanospheres (0.5 g) were added to deionized water (30 mL) and stirred for 20 min. The mixture was then transferred into a Teflon™-lined stainless-steel autoclave at 150°C for 3 h. After cooling to room temperature naturally, the precipitate was filtered, washed, and dried at 80°C and calcined at 500°C to obtain HMW-CeO 2 . Preparation of Hollow Multiporous-Walled CuO@CeO 2 (HMW-CuO@CeO 2 ):The HMW-CuO@CeO 2 catalysts with different CuO content (6, 12, 18, 24 mol-%) were prepared using a hydrothermal method. For a typical synthesis of HMW-CuO@CeO 2 (12 mol-%), Cu(CH 3 COO) 2 ·H 2 O (0.139 g) was dissolved in ultrapure water (30 mL) whilst stirring. The as-prepared HMW-CeO 2 was then added to the above solution and stirred for 30 min. The obtained slurry was transferred into a Teflon™-lined stainless-steel autoclave at 120°C for 12 h and was cooled to room temperature naturally. Finally, the precipitate was filtered, washed, and dried at 80°C to obtain HMW-CuO@CeO 2 (12 mol-%). Catalyst CharacterizationPowder X-ray diffraction (XRD) analysis was performed to verify the crystallographic phase of the catalysts present. XRD patterns of the samples were recorded with a Rigaku D/MAX-RB X-ray diffractometer, with a target of Cu-K α , operated at 60 kV and 55 mA, with a scanning speed of 5°min -1 . The 2θ of the wide angle ranged from 20°to 80°and the 2θ of the small angle ranged from 0.6°to 5°.Transmission electron microscopy (TEM) experiments were measured with a JEOL JEM-2010 transmission electron microscope Eur.

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Section: Introductionmentioning

confidence: 99%

The Template‐Free Synthesis of CuO@CeO₂ Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

Yuan

Ning

et al. 2018

Eur J Inorg Chem

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“…According to the previous literature, the oxide-supported Pt cations can be responsible for the activation of adsorbed CO molecules, weakening Pt–CO bonds, and promoting catalytic activity. , Meanwhile, CO adsorption/activation on oxidized copper species has been reported to be possible as well. Previous reports confirmed that the exposure of CuO–CeO 2 to CO can produce reduced Cu(I) species, which benefits the CO reactive adsorption and subsequent conversion of CO to CO 2 . − As a result, the formation of Pt δ+ –CO and Cu + –CO double active sites in Pt/CuO x –CeO 2 MS composites can simultaneously contribute to the CO molecule adsorption and synergistically facilitate the activation of adsorbed CO, thus greatly enhancing their catalytic activity for CO oxidation reaction. − …”

Section: Resultsmentioning

confidence: 77%

Pt-Embedded CuO_x–CeO₂ Multicore–Shell Composites: Interfacial Redox Reaction-Directed Synthesis and Composition-Dependent Performance for CO Oxidation

et al. 2018

ACS Appl. Mater. Interfaces

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Exploring the state-of-the-art heterogeneous catalysts has been a general concern for sustainable and clean energy. Here, Pt-embedded CuO -CeO multicore-shell (Pt/CuO -CeO MS) composites are fabricated at room temperature via a one-pot and template-free procedure for catalyzing CO oxidation, a classical probe reaction, showing a volcano-shaped relationship between the composition and catalytic activity. We experimentally unravel that the Pt/CuO -CeO MS composites are derived from an interfacial autoredox process, where Pt nanoparticles (NPs) are in situ encapsulated by self-assembled ceria nanospheres with CuO clusters adhered through deposition/precipitation-calcination process. Only Cu-O and Pt-Pt coordination structures are determined for CuO clusters and Pt NPs in Pt/CuO -CeO MS, respectively. Importantly, the close vicinity between Pt and CeO benefits to more oxygen vacancies in CeO counterparts and results in thin oxide layers on Pt NPs. Meanwhile, the introduction of CuO clusters is crucial for triggering synergistic catalysis, which leads to high resistance to aggregation of Pt NPs and improvement of catalytic performance. In CO oxidation reaction, both Pt-CO and Cu-CO can act as active sites during CO adsorption and activation. Nonetheless, redundant content of Pt or Cu will induce a strongly bound Pt-O-Ce or Cu-[O ]-Ce structures in air-calcinated Pt/CuO-CeO MS composites, respectively, which are both deleterious to catalytic reactivity. As a result, the composition-dependent catalytic activity and superior durability of Pt/CuO -CeO MS composites toward CO oxidation reaction are achieved. This work should be instructive for fabricating desirable multicomponent catalysts composed of noble metal and bimetallic oxide composites for diverse heterogeneous catalysis.

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“…It is well‐known that SnO 2 possesses abundant active surface deficient oxygen species and its lattice oxygen is reducible, hence a concerted interaction could occur between RuO 2 and SnO 2 to promote the reaction performance . To understand and confirm this effect, the activity of 2 % and 5 % Ru/SiO 2 was also evaluated under the same condition for comparison purpose.…”

Section: Resultsmentioning

confidence: 99%

“…It is well-known that SnO 2 possesses abundant active surface deficient oxygen species and its lattice oxygen is reducible, hence a concerted interaction could occur between RuO 2 and SnO 2 to promote the reaction performance. [23] To understand and confirm this effect, the activity of 2 % and 5 % Ru/SiO 2 was also evaluated under the same condition for comparison purpose. It is particularly mentioned here that as a rigid support without active oxygen species, SiO 2 lacks the concerted interaction with the supported active components, [24] such as RuO 2 in this study.…”

Section: Activity Evaluationmentioning

confidence: 99%

The Influence of RuO₂Distribution and Dispersion on the Reactivity of RuO₂−SnO₂Composite Oxide Catalysts Probed by CO Oxidation

Liu

Huang

et al. 2019

ChemCatChem

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To elucidate the distribution and dispersion of RuO2 species on the reactivity, RuO2−SnO2 catalysts with 2 % and 5 % Ru contents have been prepared with impregnation (IMP), deposition‐precipitation (DP) and co‐precipitation (CP) methods, and probed by CO oxidation. With IMP and DP methods, RuO2 crystallites are predominantly formed on the catalyst surface, which is favorable for CO oxidation. Moreover, the IMP catalyst possesses surface RuO2 having smaller mean crystallite size and better dispersion than the DP catalyst, thus SnRuO‐IMP displays higher activity than SnRuO‐DP at the same Ru loadings. However, with CP method, RuO2 species is mainly present as Ru4+ cations in the lattice of rutile SnO2 to form a solid solution structure below the lattice capacity, which is less reactive than the surface RuO2 due to the restriction by the SnO2 lattice. In conclusion, surface RuO2 is revealed to be the active species, whose amount and dispersion determine the activity of the catalysts. By changing preparation methods, the distribution of RuO2 species in the catalysts is varied and impacts the reactivity of the catalysts evidently. The traditional impregnation is found to be the best method to prepare RuO2−SnO2, which shows the highest activity among all the catalysts.

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Synergetic Catalytic Effects in Tri‐Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation

Cited by 17 publications

References 74 publications

The Template‐Free Synthesis of CuO@CeO₂ Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

The Template‐Free Synthesis of CuO@CeO₂ Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

Pt-Embedded CuO_x–CeO₂ Multicore–Shell Composites: Interfacial Redox Reaction-Directed Synthesis and Composition-Dependent Performance for CO Oxidation

The Influence of RuO₂Distribution and Dispersion on the Reactivity of RuO₂−SnO₂Composite Oxide Catalysts Probed by CO Oxidation

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Synergetic Catalytic Effects in Tri‐Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation

Cited by 17 publications

References 74 publications

The Template‐Free Synthesis of CuO@CeO2 Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

The Template‐Free Synthesis of CuO@CeO2 Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

Pt-Embedded CuOx–CeO2 Multicore–Shell Composites: Interfacial Redox Reaction-Directed Synthesis and Composition-Dependent Performance for CO Oxidation

The Influence of RuO2Distribution and Dispersion on the Reactivity of RuO2−SnO2Composite Oxide Catalysts Probed by CO Oxidation

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The Template‐Free Synthesis of CuO@CeO₂ Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

The Template‐Free Synthesis of CuO@CeO₂ Nanospheres: Facile Strategy, Structure Optimization, and Enhanced Catalytic Activity toward CO Oxidation

Pt-Embedded CuO_x–CeO₂ Multicore–Shell Composites: Interfacial Redox Reaction-Directed Synthesis and Composition-Dependent Performance for CO Oxidation

The Influence of RuO₂Distribution and Dispersion on the Reactivity of RuO₂−SnO₂Composite Oxide Catalysts Probed by CO Oxidation