Opportunities and challenges in the development of advanced materials for emission control catalysts

Datye, Abhaya K.; Votsmeier, Martin

doi:10.1038/s41563-020-00805-3

Cited by 147 publications

(110 citation statements)

References 97 publications

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“…It also showed good cycling stability as no deactivation in low‐temperature CO oxidation was observed after repeated light‐off measurements (Figure 2 a). Although the reductive treatment on Pt 1 /CeO 2 _AT can enhance the low‐temperature performance (i.e., decreased T 10 , T 50 , and T 90 in Figure 2 b, right) by forming Pt NPs, [7] the so‐called activated catalyst is susceptible to drastic activity loss (nearly back to the original T 10 , T 50 , and T 90 in Figure 2 b, right) once being oxidized at temperatures >400 °C [2d] . This is consistent with previous experimental observations by Gänzler et al.…”

Section: Resultsmentioning

confidence: 99%

Tailoring the Local Environment of Platinum in Single‐Atom Pt₁/CeO₂ Catalysts for Robust Low‐Temperature CO Oxidation

Jiang

Yao

et al. 2021

Angewandte Chemie

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A single‐atom Pt1/CeO2 catalyst formed by atom trapping (AT, 800 °C in air) shows excellent thermal stability but is inactive for CO oxidation at low temperatures owing to over‐stabilization of Pt2+ in a highly symmetric square‐planar Pt1O4 coordination environment. Reductive activation to form Pt nanoparticles (NPs) results in enhanced activity; however, the NPs are easily oxidized, leading to drastic activity loss. Herein we show that tailoring the local environment of isolated Pt2+ by thermal‐shock (TS) synthesis leads to a highly active and thermally stable Pt1/CeO2 catalyst. Ultrafast shockwaves (>1200 °C) in an inert atmosphere induced surface reconstruction of CeO2 to generate Pt single atoms in an asymmetric Pt1O4 configuration. Owing to this unique coordination, Pt1δ+ in a partially reduced state dynamically evolves during CO oxidation, resulting in exceptional low‐temperature performance. CO oxidation reactivity on the Pt1/CeO2_TS catalyst was retained under oxidizing conditions.

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Section: Resultsmentioning

confidence: 99%

Tailoring the Local Environment of Platinum in Single‐Atom Pt₁/CeO₂ Catalysts for Robust Low‐Temperature CO Oxidation

Jiang

Yao

et al. 2021

Angewandte Chemie

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“…Gänzler et al [22] utilized such fundamental insights for rational in situ tuning of the active sites of a Pt/CeO2 DOC in order to enhance its catalytic activity for CO oxidation. As recently summarized in a review article by Datye and Votsmeier [23], also the catalyst preparation and the optimization of the catalyst formulation can maximize activity and stability.…”

Section: Introductionmentioning

confidence: 99%

Effects of Hydrothermal Aging on CO and NO Oxidation Activity over Monometallic and Bimetallic Pt-Pd Catalysts

et al. 2021

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By combining scanning transmission electron microscopy, CO chemisorption, and energy dispersive X-ray spectroscopy with CO and NO oxidation light-off measurements we investigated deactivation phenomena of Pt/Al2O3, Pd/Al2O3, and Pt-Pd/Al2O3 model diesel oxidation catalysts during stepwise hydrothermal aging. Aging induces significant particle sintering that results in a decline of the catalytic activity for all catalyst formulations. While the initial aging step caused the most pronounced deactivation and sintering due to Ostwald ripening, the deactivation rates decline during further aging and the catalyst stabilizes at a low level of activity. Most importantly, we observed pronounced morphological changes for the bimetallic catalyst sample: hydrothermal aging at 750 °C causes a stepwise transformation of the Pt-Pd alloy via core-shell structures into inhomogeneous agglomerates of palladium and platinum. Our study shines a light on the aging behavior of noble metal catalysts under industrially relevant conditions and particularly underscores the highly complex transformation of bimetallic Pt-Pd diesel oxidation catalysts during hydrothermal treatment.

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“…This is in agreement with a recent work showing that clusters of Pt oxide (for example Pt 8 O 14 containing Pt-O-Pt sites) are more active in CO oxidation 39 than single atom Pt. We should note that even higher CO oxidation reactivity can be achieved by reducing Pt/CeO 2 catalysts 38,40 , but our focus here is on the oxidized state of the catalyst which is encountered during lean methane oxidation. Under the lean conditions (excess oxygen), the CO oxidation reactivity is reproducible over multiple runs.…”

Section: Resultsmentioning

confidence: 99%

Engineering catalyst supports to stabilize Pd/PdO 2D rafts for water-tolerant methane oxidation

Xiong¹,

Kunwar²,

García‐Vargas³

et al. 2020

Preprint

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The size and morphology of the active phase (metal or metal oxide) are critical for the performance of heterogeneous catalysts. Conventional approaches for catalyst synthesis involve the modification of pore size and structure, the use of ligands to anchor the metal during preparation or the use of nanostructured oxides with well-defined facets to provide suitable sites for metal nucleation and growth. However, these approaches may not yield durable catalysts for high temperature applications, such as the treatment of unburnt methane from natural gas fueled engines. Here we demonstrate an approach that relies on the trapping of metal single atoms on the support surface, in thermally stable form, to modify the nature of deposited metal/metal oxide clusters. By anchoring Pt ions on the catalyst support we can tailor the morphology of the deposited phase. In particular, two-dimensional (2-D) rafts of Pt/PtOx on the engineered catalyst support are formed by this approach, as opposed to three-dimensional (3-D) metal oxide nanoparticles on conventional supports. Adopting this approach for the synthesis of bimetallic catalysts via addition of Pd to the atom-trapped catalyst support (Pt@CeO2) we found that the resulting Pd/Pt@CeO2 catalyst provides improved thermal stability and water tolerance during methane oxidation. We attribute the improved performance to the 2-D morphology of the Pd/PdO phase present on the atom-trapped catalyst support. The results show that modifying the support by trapping single atoms could provide an important addition to the toolkit of catalyst designers to engineer catalyst supports for controlling the nucleation and growth of metal and metal oxide clusters in heterogeneous catalysts.

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Opportunities and challenges in the development of advanced materials for emission control catalysts

Cited by 147 publications

References 97 publications

Tailoring the Local Environment of Platinum in Single‐Atom Pt₁/CeO₂ Catalysts for Robust Low‐Temperature CO Oxidation

Tailoring the Local Environment of Platinum in Single‐Atom Pt₁/CeO₂ Catalysts for Robust Low‐Temperature CO Oxidation

Effects of Hydrothermal Aging on CO and NO Oxidation Activity over Monometallic and Bimetallic Pt-Pd Catalysts

Engineering catalyst supports to stabilize Pd/PdO 2D rafts for water-tolerant methane oxidation

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Opportunities and challenges in the development of advanced materials for emission control catalysts

Cited by 147 publications

References 97 publications

Tailoring the Local Environment of Platinum in Single‐Atom Pt1/CeO2 Catalysts for Robust Low‐Temperature CO Oxidation

Tailoring the Local Environment of Platinum in Single‐Atom Pt1/CeO2 Catalysts for Robust Low‐Temperature CO Oxidation

Effects of Hydrothermal Aging on CO and NO Oxidation Activity over Monometallic and Bimetallic Pt-Pd Catalysts

Engineering catalyst supports to stabilize Pd/PdO 2D rafts for water-tolerant methane oxidation

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Tailoring the Local Environment of Platinum in Single‐Atom Pt₁/CeO₂ Catalysts for Robust Low‐Temperature CO Oxidation

Tailoring the Local Environment of Platinum in Single‐Atom Pt₁/CeO₂ Catalysts for Robust Low‐Temperature CO Oxidation