High performance diesel oxidation catalysts using ultra-low Pt loading on titania nanowire array integrated cordierite honeycombs

Hoang, Son; Lu, Xingxu; Tang, Wenxiang; Wang, Sibo; Du, Shoucheng; Nam, Chang‐Yong; Ding, Y.; Vinluan, Rodrigo D.; Zheng, Jie; Gao, Pu‐Xian

doi:10.1016/j.cattod.2017.11.019

Cited by 34 publications

(12 citation statements)

References 46 publications

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“…It is noted that pure rutile phase, the most thermodynamically stable among TiO 2 polymorphs as typical oxidation catalyst support materials 26,27 , is realized in the form of TiO 2 NA forest in this study. Additionally, the hierarchically structured NA forest allows efficient mass transport and good catalytic performance in supported catalysts in a honeycomb monolithic device form, with advantageous attributes, such as low pressure drop and high surface area 28 . In this work, densely packed forest of mesoporous rutile TiO 2 NA was successfully grown onto channel surfaces of cordierite honeycombs with various sizes ranging from a size of 0.2 L (63 mm × 63 mm × 50 mm), to a full-size core of 1.2 L (Ф 145 mm × 75 mm).…”

Section: Resultsmentioning

confidence: 99%

“…16) as two references. These reference catalysts were prepared by etching of cordierite honeycombs followed by Pt dip-coating, and atomic layer deposition of Pt over TiO 2 NA monolith 28 , respectively. It is noted the low-temperature DOC activity of Pt NP/TiO 2 nanoarray is good, but inferior to Pt 1 /TiO 2 NA, despite a 2.5-time higher PGM loading (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Activating low-temperature diesel oxidation by single-atom Pt on TiO2 nanowire array

et al. 2020

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Supported metal single atom catalysts (SACs) present an emerging class of low-temperature catalysts with high reactivity and selectivity, which, however, face challenges on both durability and practicality. Herein, we report a single-atom Pt catalyst that is strongly anchored on a robust nanowire forest of mesoporous rutile titania grown on the channeled walls of fullsize cordierite honeycombs. This Pt SAC exhibits remarkable activity for oxidation of CO and hydrocarbons with 90% conversion at temperatures as low as~160 o C under simulated diesel exhaust conditions while using 5 times less Pt-group metals than a commercial oxidation catalyst. Such an excellent low-temperature performance is sustained over hydrothermal aging and sulfation as a result of highly dispersed and isolated active single Pt ions bonded at the Ti vacancy sites with 5 or 6 oxygen ions on titania nanowire surfaces.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Activating low-temperature diesel oxidation by single-atom Pt on TiO2 nanowire array

et al. 2020

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“…Platinum nanoparticles were loaded onto the prepared supports through a wet-impregnation process. 30 For the LPT and ANT-TiO 2 nano-array-rooted monoliths, the honeycombs were cut into cuboids of 1 cm × 1 cm × 2 cm and soaked in 20 mL of platinum aqueous solution (0.1766 mg/mL Pt 2+ ) of tetraammineplatinum(II) nitrate (H 12 N 6 O 6 Pt, 99.99% metals basis, Alfa Aesar) and aged for 12 h at 80 °C. The solution was then evaporated in the open air at 80 °C until dry.…”

Section: Methodsmentioning

confidence: 99%

Ion-Exchange Loading Promoted Stability of Platinum Catalysts Supported on Layered Protonated Titanate-Derived Titania Nanoarrays

Lu¹,

Tang²,

Du³

et al. 2019

ACS Appl. Mater. Interfaces

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Supported metal catalysts are one of the major classes of heterogeneous catalysts, which demand good stability in both the supports and catalysts. Herein, layered protonated titanate-derived TiO2 (LPT-TiO2) nanowire arrays were synthesized to support platinum catalysts using different loading processes. The Pt ion-exchange loading on pristine LPTs followed by thermal annealing resulted in superior Pt catalysts supported on the LPT-TiO2 nanoarrays with excellent hydrothermal stability and catalytic performance toward CO and NO oxidations as compared to the Pt catalysts through wet-impregnation on the anatase TiO2 (ANT-TiO2) nanoarrays resulted from thermal annealing of LPT nanoarrays. Both loading processes resulted in highly dispersed Pt nanoparticles (NPs) with average sizes smaller than 1 nm at their pristine states. However, after hydrothermal aging at 800 °C for 50 h, highly dispersed Pt NPs were only retained on the ion-exchanged LPT-TiO2 nanoarrays with the support structure consisting of a mixture of 74% anatase and 26% rutile TiO2. For the wet-impregnation loading directly on anatase TiO2 nanoarrays derived from LPT, the Pt catalysts experienced severe agglomeration after hydrothermal aging, with the nanoarray supports consisting of 86% anatase and 14% rutile TiO2. Spectroscopy analysis suggested that Pt2+ cations intercalated into the interlayers of the titanate frameworks through ion-exchange impregnation procedure, which altered the chemical and electronic structures of the catalysts, resulting in the shifts of the electronic binding energy, Raman bands, and optical energy bandgap. The ion-exchangeable nature of LPT nanoarrays clearly provides a structural modification in Pt-doped LPT that has resulted in a strong interaction between the Pt catalysts and LPT-TiO2 nanoarray supports, leading to the enhanced hydrothermal stability of the catalysts. Considering the wide applications of the LPT and TiO2 nanomaterials as supports for catalysts, this finding provides a new pathway to design highly stable supported metal catalysts for different reactions.

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“…Titania and titanate nanostructures and their chemically doped and cocatalyst decorated derivatives have been extensively studied in degrading organic impurities being present water as well as on solid surfaces. While the electrons accumulated typically on the co-catalyst nanoparticles (Pt, Pd, Rh) are expected to interact with unsaturated and aromatic bonds in organic moieties, the holes on the surface of TiO 2 are responsible for the initiation of oxidative processes that may result in C-C bond scission, dehydrogenation and the like [55][56][57][58][59][60][61][62]. Recently, platinum catalysts supported on layered protonated titanate-derived titania nanoarrays were found to have a high activity in CO and NO oxidation as compared to Pt catalysts through wet-impregnation on the anatase TiO 2 [63].…”

Section: General Surwaymentioning

confidence: 99%

“…The hydrogenation of CO 2 was studied extensively on titania (TiO 2 ) supported Rh [20][21][22][23][24][91][92][93] and the reaction was also investigated on titanate (TiONW and TiONT)-supported Rh recently [62,90,94]. In all cases, the supported Rh showed an excellent catalytic activity.…”

Section: Co 2 Hydrogenation On Titania and Titanate Supported Rhmentioning

confidence: 99%

Rh-induced Support Transformation and Rh Incorporation in Titanate Structures and Their Influence on Catalytic Activity

et al. 2020

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Rh is one of the most effective metals in several technologically important heterogeneous catalytic reactions, like the hydrogenation of CO2, and CO, the CO+H2O reaction, and methane and ethanol transformations. Titania and titanates are among the most frequently studied supports for Rh nanoparticles. The present study demonstrates that the nature of the support has a marked influence on the specific activity. For comparison, the catalytic activity of TiO2 P25 is also presented. It is pointed out that a certain amount of Rh can be stabilized as cation (Rh+) in ion-exchange positions (i.e., in atomic scale distribution) of the titanate framework. This ionic form does not exists on TiO2. We pay distinguished attention not only to the electronic interaction between Rh metal and the titania/titanate support, but also to the Rh-induced phase transitions of one-dimensional titanate nanowires (TiONW) and nanotubes (TiONT). Support transformation phenomena can be observed in Rh-loaded titanates. Rh decorated nanowires transform into the TiO2(B) phase, whereas their pristine counterparts recrystallize into anatase. The formation of anatase is dominant during the thermal annealing process in both acid-treated and Rh-decorated nanotubes; Rh catalysis this transformation. We demonstrate that the phase transformations and the formation of Rh nanoclusters and incorporated Rh ions affect the conversion and the selectivity of the reactions. The following initial activity order was found in the CO2 + H2, CO + H2O and C2H5OH decomposition reactions: Rh/TiO2 (Degussa P25) ≥ Rh/TiONW > Rh/TiONT. On the other hand it is remarkable that the hydrogen selectivity in ethanol decomposition was two times higher on Rh/TiONW and Rh/TiO(NT) catalysts than on Rh/TiO2 due to the presence of Rh+ cations incorporated into the framework of the titanate structures.

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High performance diesel oxidation catalysts using ultra-low Pt loading on titania nanowire array integrated cordierite honeycombs

Cited by 34 publications

References 46 publications

Activating low-temperature diesel oxidation by single-atom Pt on TiO2 nanowire array

Activating low-temperature diesel oxidation by single-atom Pt on TiO2 nanowire array

Ion-Exchange Loading Promoted Stability of Platinum Catalysts Supported on Layered Protonated Titanate-Derived Titania Nanoarrays

Rh-induced Support Transformation and Rh Incorporation in Titanate Structures and Their Influence on Catalytic Activity

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