Effect of Cu substitution on the structure and reactivity of CuxCo3-xO4 spinel catalysts for direct NOx decomposition

Roberts, Charles A.; Paidi, Vinod K.; Shepit, Michael; Peck, Torin C.; Masias, Kimber L. Stamm; Lierop, J. van; Reddy, Gunugunuri K.

doi:10.1016/j.cattod.2020.05.050

Cited by 17 publications

(20 citation statements)

References 33 publications

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“…However, pure Co 3 O 4 spinel oxide usually shows inferior catalytic activity and thereafter cannot meet the actual industrial demand . Therefore, researchers have modified the Co 3 O 4 catalyst by various means to improve its catalytic performance. − Wei et al proposed that appropriate doping of cations and precise control of their loading and location could significantly improve the catalytic performance of Co 3 O 4 . He et al found that the effect of Ce/Co ratios distinctively influence the catalytic activities of Ce x Co 3– x O 4 composite oxides for N 2 O catalytic decomposition and that the synergistic effect present between Co and Ce could not only inhibit the crystallization of Co 3 O 4 but also promote the formation of Co 3+ and oxygen vacancies, thereby improving the catalytic performance of the catalyst .…”

Section: Introductionmentioning

confidence: 99%

Taming the Redox Property of A_0.5Co_2.5O₄ (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N₂O Decomposition

Sun

Wang

Zhang

et al. 2021

ACS Appl. Energy Mater.

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Nitrous oxide (N2O) originating from the combustion of fossil fuels causes serious environmental issues. The design and construction of a catalyst with high performance for the removal of N2O remains challenging. Herein, a series of alkaline-earth metal-modified A0.5Co2.5O4 (A = Mg, Ca, Sr, Ba) catalysts were initiated by a hydrothermal protocol, and their catalytic activities for N2O decomposition were systematically investigated by experimental and density functional theory calculation. The results reveal that the doping of alkaline-earth metals significantly affects the morphology, structure, active oxygen species, oxygen vacancy, and redox property and thereafter the catalytic activity of A0.5Co2.5O4 for N2O catalytic decomposition. The introduction of alkaline-earth metals (A = Ca, Sr, Ba) considerably promoted the reduction of Co3+ to Co2+, thereby improving the electron-donating ability and oxygen vacancy number and thereafter weakening the Co–O bond. As a result, the catalytic activity of N2O decomposition distinctively enhanced. Among them, Ba0.5Co2.5O4 shows optimal N2O decomposition performance by virtue of its outstanding active oxygen species and excellent redox property. However, the doping of Mg suppresses the electron-donating ability of Mg0.5Co2.5O4 and thereafter the catalytic activity for N2O decomposition. Therefore, this work may shine light on the understanding of N2O decomposition over alkaline-earth metal-modified Co-based oxides.

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Section: Introductionmentioning

confidence: 99%

Taming the Redox Property of A_0.5Co_2.5O₄ (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N₂O Decomposition

Sun

Wang

Zhang

et al. 2021

ACS Appl. Energy Mater.

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“…Previous work by some of the current authors reported that spinel Co x Cu 3−x O 4 was an active family of catalysts for direct NO decomposition. 57 This result was apparently "re-discovered" by the AI agent. Among the 35 compounds examined during optimization, cobalt and copper regularly co-presented in nearly every formula, as shown in Figure 4a.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…49 Our study was motivated by the recent discovery by some of the current authors that Cu-substituted spinel Co x Cu 3−x O 4 oxide is a family of effective catalysts for direct NO decomposition at a moderate temperature (∼450 °C). 57 Drawing inspiration from the improved performance of spinel oxides with three to five 3d transition-metal (3d-TM) species for catalytic and energy applications, 17,58−60 we expect that better catalytic activity for direct NO decomposition could be achieved by strategically tailoring appropriate metal components as well as their correct ratios in the spinel structure. The design of the direct NO decomposition catalyst is therefore formulated as a black-box optimization of the multicomponent ).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The design of the direct NO decomposition catalyst is therefore formulated as a black-box optimization of the multicomponent ). 57 This observation indicates the intuition-driven attempt to find a better spinel oxide for direct NO decomposition in the broad combinations of 3d transition-metal elements was no more efficient than the brute-force examination in the subspace of binary Co x Cu 3−x O 4 , as employed in ref 57, thus further illuminating the material discovery challenge and motivating our goal of discovering a better catalyst under the guidance of ML.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Descriptor-Free Design of Multicomponent Catalysts

Zhang¹,

Peck²,

Reddy³

et al. 2022

ACS Catal.

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Multicomponent alloys and oxides are material systems, offering the great promise of unique yet advantageous catalytic properties through appropriate choice of compositions. However, strategic design of the highly active multicomponent catalyst is challenged by the vast number of potential candidates and complex inter-component effects. Herein, we demonstrate the successful employment of Bayesian optimization (BO) to improve the experimental measured activity as a direct function of compositional variables without educating physical knowledge to the machine. We applied BO in screening spinel Cr a Mn b Fe c Co d Ni e Cu f Zn 3−a−b−c−d−e−f O 4 for the decomposition of nitric oxide into environmentally friendly nitrogen.Starting with 30 manually surveyed samples, 35 more samples were measured, and six oxides were discovered with higher specific activities. The best candidate discovered in the current work, Co 2.1 Cu 0.6 Zn 0.2 Mn 0.1 O 4 , showed significantly better catalytic performance than the benchmark standard. Although not directly educated about the underlying physical origin of variation in specific activity, the optimization balanced the exploration to locate promising regions and exploitation to survey in the identified region of Mn-containing subspace. The success to directly optimize the experimental measured specific activity in the large compositional space through a small sampled data set demonstrates the great potential of BO in the discovery and design of multicomponent catalysts.

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“…Xu et al added 40% BaCO 3 to MgCo 2 O 4 , and the catalyst activity increased from 69.7 to 99%, indicating that the addition of BaCO 3 can significantly reduce the apparent activation energy significantly. Roberts et al found that, after Cu doping, the NO catalytic activity of Cu 0.4 Co 2.6 O 4 was improved and the amount of N 2 O produced was also reduced. Reddy et al found that CeO 2 itself does not have NO decomposition activity but can exhibit high activity when combined with Co and Ni oxides.…”

Section: Catalytic Decomposition Of No: Catalystsmentioning

confidence: 99%

Advances in De-NO_x Methods and Catalysts for Direct Catalytic Decomposition of NO: A Review

2021

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China is the country with the most coal-power generation and the most diesel vehicles in the world; it is of great significance to research the reduction of NO emissions. This paper summarizes five de-NO x methods, including adsorption, storage reduction, selective catalytic reduction, selective non-catalytic reduction, and direct catalytic decomposition, and explores the current research state and problems existing in actual application of each method. The direct catalytic decomposition method is focused especially, and research progresses of six major catalysts used in this method are summarized, including noble metals, metal oxides, perovskite-type composite oxide, hydrotalcite materials, heteropoly acid, and Cu–ZSM-5. The activity and O2 tolerance of each catalyst are compared, and future research directions are given. Cu–ZSM-5 is studied in detail as a result of its high activity and O2 tolerance and reviewed from three aspects, including the influence of preparation and reaction conditions on activity, the mechanism of catalytic decomposition, and doping modification. Finally, the future research directions of NO decomposition are discussed.

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Effect of Cu substitution on the structure and reactivity of CuxCo3-xO4 spinel catalysts for direct NOx decomposition

Cited by 17 publications

References 33 publications

Taming the Redox Property of A_0.5Co_2.5O₄ (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N₂O Decomposition

Taming the Redox Property of A_0.5Co_2.5O₄ (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N₂O Decomposition

Descriptor-Free Design of Multicomponent Catalysts

Advances in De-NO_x Methods and Catalysts for Direct Catalytic Decomposition of NO: A Review

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Effect of Cu substitution on the structure and reactivity of CuxCo3-xO4 spinel catalysts for direct NOx decomposition

Cited by 17 publications

References 33 publications

Taming the Redox Property of A0.5Co2.5O4 (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N2O Decomposition

Taming the Redox Property of A0.5Co2.5O4 (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N2O Decomposition

Descriptor-Free Design of Multicomponent Catalysts

Advances in De-NOx Methods and Catalysts for Direct Catalytic Decomposition of NO: A Review

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Taming the Redox Property of A_0.5Co_2.5O₄ (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N₂O Decomposition

Taming the Redox Property of A_0.5Co_2.5O₄ (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N₂O Decomposition

Advances in De-NO_x Methods and Catalysts for Direct Catalytic Decomposition of NO: A Review