The effect of Pt/Pd ratio on the oxidation activity and resistance to sulfur poisoning for Pt-Pd/BEA diesel oxidation catalysts with high siliceous content

Ho, Phuoc Hoang; Shao, Jieling; Yao, Dawei; Ilmasani, Rojin Feizie; Salam, Muhammad Abdus; Creaser, Derek; Olsson, Louise

doi:10.1016/j.jece.2022.108217

Cited by 23 publications

(12 citation statements)

References 55 publications

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“…Pt and Pd can both catalyze CO oxidation. A DOC needs to oxidize all three components, , and Pt and Pd are beneficial, but the synergy between Pt and Pd is not well understood. Since these catalysts operate under oxidizing conditions and are subject to accelerated aging at 800 °C, it is important to understand the microstructure of the working catalysts after the recommended aging protocols.…”

Section: Introductionmentioning

confidence: 99%

Biphasic Janus Particles Explain Self-Healing in Pt–Pd Diesel Oxidation Catalysts

et al. 2023

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The addition of Pd to Pt-based diesel oxidation catalysts is known to enhance performance and restrict the anomalous growth of Pt nanoparticles when subjected to aging at high temperatures in oxidative environments. To gain a mechanistic understanding, we studied the transport of the mobile Pt and Pd species to the vapor phase, since vapor phase transport is the primary route for sintering in these catalysts. The results are surprising: there is a 30-fold drop in the effective vapor pressure of Pt in the Pt−Pd catalysts compared to monometallic Pt. At the same time, there is a significant enhancement in the vapor pressure of Pd, compared to PdO, which otherwise has a negligible vapor pressure at the aging temperature. Such behavior cannot be explained simply by alloying Pt and Pd in the metallic phase, or a core−shell morphology where a PdO shell covers a Pt core. Transmission electron microscopic examination of catalysts aged up to 50 h in air at 800 °C shows that the particles exhibit a biphasic "Janus"-like structure. The metal and oxide phases are conjoined, exposing a metal and an oxide face to the gas phase. The high mobility of the Pt and Pd allows them to be partitioned into the metal and oxide phases, in apparent thermodynamic equilibrium. The PdO helps to trap mobile PtO 2 and as a result contains high concentrations of Pt oxide, consistent with its role in mitigating the transport of Pt to the vapor phase and preventing the growth of anomalously large particles. In turn, Pt allows Pd to remain metallic, allowing the catalyst to retain both metal and oxide functionality for catalysis. The regeneration of deactivated catalysts typically requires an external input, such as a change in the working environment from reducing to oxidizing or vice-versa. Here, we show that the mobile species, which are primary contributors to catalyst sintering are effectively returned to the active site, hence our use of the term "selfhealing". The detailed insights into the inner workings of the Pt−Pd diesel oxidation catalysts can help provide clues to the design of robust and durable heterogeneous catalysts.

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Section: Introductionmentioning

confidence: 99%

Biphasic Janus Particles Explain Self-Healing in Pt–Pd Diesel Oxidation Catalysts

et al. 2023

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“…Subsequently, the group prepared a series of catalysts supported on high-silica BEAs with different Pt/Pd ratios using the initial impregnation method. 220 The formation of Pt−Pd alloys led to contraction of the Pt lattice in the catalysts. This phenomenon not only improved the sintering resistance of Pt but also retained high percentage of Pd 2+ .…”

Section: Application Of Porous Metal Oxide Catalysts In Diesel Oxidat...mentioning

confidence: 99%

“…This indicates that by adjusting the SAR of zeolite, the redox ability of the catalyst can be changed, and the stability of the catalyst can be improved. Subsequently, the group prepared a series of catalysts supported on high-silica BEAs with different Pt/Pd ratios using the initial impregnation method . The formation of Pt–Pd alloys led to contraction of the Pt lattice in the catalysts.…”

Section: Application Of Porous Metal Oxide Catalysts For Catalytic Pu...mentioning

confidence: 99%

Research Progress on Preparation of Metal Oxide Catalysts with Porous Structure and Their Catalytic Purification of Diesel Engine Exhausts Gases

Zhou,

Wang,

Gao

et al. 2024

ACS Catal.

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Because of their special physicochemical properties, pore-structured metal oxide catalysts are widely used in environmental catalysis, energy chemicals, fuel cells, medicine, and other related fields. In recent years, these oxides have also been increasingly studied in the catalytic purification of diesel engine exhaust gases. In this paper, the research progresses of preparation methods of porous metal oxide catalysts and their application in the catalytic purification of diesel engine exhaust were reviewed. The advantages and disadvantages of different methods for the synthesis of porous metal oxide catalysts were elaborated, as well as the mechanism comparison of different types of porous metal oxide catalysts in catalytic purification of diesel engine exhaust pollutants. Finally, the current issues on the preparation of porous metal oxide catalysts and their development trends in application of diesel engine exhaust purification were summarized and discussed. The pore-structured metal oxide catalysts are beneficial for improving the contact efficiency between catalysts and pollutants, which can enhance the catalytic purification efficiency of catalysts. Meanwhile, the intrinsic activity is the most fundamental factor for determining their catalytic activity except for porous structure effects. In addition, this paper can help researchers to deeply understand the important effect of porous metal oxide catalysts in the treatment of diesel engine exhaust pollutants and provide theoretical guidance for the design and development of high-efficiency catalysts.

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“…37,38 Compared with the monometallic Pd and Pt catalysts, Pt−Pd bimetallic catalysts showed significantly stronger sulfur resistance and easier regeneration of deactivated catalysts. 39,40 It has been reported that the affinity between the Pt catalyst and SO 2 could be weakened in the Pt−Ru bimetallic system. 41 In addition, Zheng et al prepared a solid solution of ZrO 2 containing BaSO 4 by precipitation as a support for preparing the Pt catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…The structure decoration is a commonly used approach to enhance catalytic performance. , Bimetallic synergistic catalysis is regarded to be an effective method to increase the catalytic activity and sulfur resistance. , Compared with the monometallic Pd and Pt catalysts, Pt–Pd bimetallic catalysts showed significantly stronger sulfur resistance and easier regeneration of deactivated catalysts. , It has been reported that the affinity between the Pt catalyst and SO 2 could be weakened in the Pt–Ru bimetallic system . In addition, Zheng et al prepared a solid solution of ZrO 2 containing BaSO 4 by precipitation as a support for preparing the Pt catalyst .…”

Section: Introductionmentioning

confidence: 99%

Ultralow Doping of Mn Species into Pt Catalyst Enhances the CO Oxidation Performance in the Presence of H₂O and SO₂

Liu,

Zou,

et al. 2023

ACS Catal.

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Bimetallic catalysts Pt–M/Ti were prepared by introducing various dopants (M = Mn, Fe, Co, Cu, Ce, Mo) into Pt/Ti with ultralow loadings (0.5 wt % M) and compared in CO oxidation in the presence of H2O and SO2. Among these catalysts, Pt–0.5Mn/Ti contributed the highest oxidation efficiency and strongest sulfur resistance. Further improvement of Mn contents led to the decrease of CO conversion. It was indicated that the introduction of appropriate Mn species enhanced the active oxygen supplying ability of the catalyst, thus improving the reaction activity. The CO oxidation performance of the catalyst was improved through the reaction between *OH from H2O dissociation and CO. The deposition of S on the Pt–0.5Mn/Ti surface did not increase with time extension. Theoretical calculation results revealed that cleavage of S–O–Mn species could be facilitated by Pt, and the SO2 adsorption energy calculations demonstrated that SO2 was more easily adsorbed on Pt/Ti than Pt–0.5Mn/Ti, which was very consistent with its sulfur resistance. In situ DRIFT studies at 260 °C revealed that the introduction of SO2 onto Pt–0.5Mn/Ti showed little change for CO adsorption on different Pt species, while Pt/Ti showed an apparent decrease of Pt0–CO. 18O isotopic experiments in the presence of H2 18O and SO2 were systematically designed to accurately quantify the CO2 composition including C16O16O, C16O18O, and C18O18O. Accordingly, the reaction mechanism for Pt–0.5Mn/Ti catalyzed CO oxidation consisting of four pathways was proposed.

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The effect of Pt/Pd ratio on the oxidation activity and resistance to sulfur poisoning for Pt-Pd/BEA diesel oxidation catalysts with high siliceous content

Cited by 23 publications

References 55 publications

Biphasic Janus Particles Explain Self-Healing in Pt–Pd Diesel Oxidation Catalysts

Biphasic Janus Particles Explain Self-Healing in Pt–Pd Diesel Oxidation Catalysts

Research Progress on Preparation of Metal Oxide Catalysts with Porous Structure and Their Catalytic Purification of Diesel Engine Exhausts Gases

Ultralow Doping of Mn Species into Pt Catalyst Enhances the CO Oxidation Performance in the Presence of H₂O and SO₂

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The effect of Pt/Pd ratio on the oxidation activity and resistance to sulfur poisoning for Pt-Pd/BEA diesel oxidation catalysts with high siliceous content

Cited by 23 publications

References 55 publications

Biphasic Janus Particles Explain Self-Healing in Pt–Pd Diesel Oxidation Catalysts

Biphasic Janus Particles Explain Self-Healing in Pt–Pd Diesel Oxidation Catalysts

Research Progress on Preparation of Metal Oxide Catalysts with Porous Structure and Their Catalytic Purification of Diesel Engine Exhausts Gases

Ultralow Doping of Mn Species into Pt Catalyst Enhances the CO Oxidation Performance in the Presence of H2O and SO2

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Ultralow Doping of Mn Species into Pt Catalyst Enhances the CO Oxidation Performance in the Presence of H₂O and SO₂