Kinetic study of CO oxidation on clean and oxidized Pt

Dahlstrøm, Per Kristian; Harrington, David A.; Seland, Frode

doi:10.1016/j.electacta.2012.04.150

Cited by 12 publications

(8 citation statements)

References 52 publications

(30 reference statements)

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“…This value is close to E a of 53 kJ mol −1 on 1−4 nm Pt clusters/ TiO 2 nanocatalysts for CO oxidation via a Mars−van Krevelen mechanism. 312 Possibly, the Pt iso species would have formal oxidation states from +4 to +1 on the TiO 2 surface that the harsh reduction condition induces the formation of mobile (PtOH) ads species 313 with strong interactions along both step and terrace sites of reducible TiO 2 at a high temperature.…”

Section: Surface Chemistry and Heterogeneous Catalysis On Mixed Catal...mentioning

confidence: 99%

Operando Surface Studies on Metal-Oxide Interfaces of Bimetal and Mixed Catalysts

et al. 2021

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The formation of metal-oxide interfaces in catalytic systems exhibits a synergistic phenomenon between metal and reducible oxides, often referred to as the strong metal−support interaction (SMSI). This unusual characteristic has been connected to the origin of highly enhanced catalytic performance for decades, but the mechanistic explanation of SMSI remains a long-standing issue in heterogeneous catalysis. To understand this matter at the molecular level, geometric and electronic functions of metal-oxide interfaces during catalytic reactions should be clearly interpreted using advanced microscopic and spectroscopic analysis techniques. In this Review, we highlight recently performed investigations at metal-oxide interfaces by operando characterization tools to identify active sites in working conditions. We introduce two kinds of catalysts, platinum-based bimetallic alloys and mixed metal-oxide catalysts. Selected operando techniques reveal their atomic-scale morphology, surface electronic structure, and charge transfer/transport at surfaces under oxidation, reduction, and gas mixture environments. With bimetallic model catalysts, topographic morphology observations present critical evidence for the structural modulation between the topmost layer and the subsurface lattice in oxygen conditions. For the mixed metal-oxide catalysts, we note that metal nanoparticles on reducible oxides demonstrate the catalytic activity enhancement, which is obviously influenced by the change of oxidation states at the metal-oxide interface. Environmental transmission electron microscopy images unveil the atomic-scale redox behaviors at the nanoparticle interfaces with evolutions of the reducible oxide under the catalytic reaction. The important role of reactive interfaces between the transition metal atom and oxide-support explains the surface chemistry and heterogeneous catalysis over active sites on well-defined single crystal model surfaces, as well as nanoparticle catalysts. Overall, operando studies for metal-oxide interfaces can shed light on mechanistic insights into the tuning of catalytic activity at the molecular level and on improving catalytic performance by the SMSI effect.

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Section: Surface Chemistry and Heterogeneous Catalysis On Mixed Catal...mentioning

confidence: 99%

Operando Surface Studies on Metal-Oxide Interfaces of Bimetal and Mixed Catalysts

et al. 2021

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“…Polarization at +0.7 V vs Ag|AgCl formed platinum oxides on the transducer surface in the alkaline environment, effectively inhibiting adsorption of CO. Unlike NO, adsorption is a key step in the electrooxidation mechanism of CO on Pt, 53 and prevention of this process allowed Jensen's sensor to achieve a −2.1 selectivity coefficient for NO against CO. In this instance, chemical modification on (Pt oxide formation) and near (PTFE membrane) the transducer surface were employed to successfully enhance selectivity.…”

Section: Chemical Modificationsmentioning

confidence: 99%

Electrochemical Nitric Oxide Sensors: Principles of Design and Characterization

2019

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Nitric oxide (NO) is a molecule of vast physiological significance, but much remains unknown about the in vivo concentration dependence of its activity, its basal level concentrations, and how levels fluctuate in the course of certain disease states. Although electrochemical methods are best suited to real-time, continuous monitoring of NO, sensors must be appropriately modified to ensure adequate selectivity, sensitivity, sensocompatibility, and biocompatibility in challenging biological environments. Herein, we provide a critical overview of recent advances in the field of electrochemical NO sensors designed to operate in physiological milieu. Unique to this review, we have opted to highlight research efforts undertaking meticulous characterization of the sensor's analytical performance. Furthermore, we compile basic recommendations to inform future electrochemical NO sensor development and facilitate cross-comparison of proposed sensor designs.

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“…The effectiveness of this treatment likely stems from the passivation or blocking of the electrochemically-active sites on the Pt-Nafion electrode towards CO oxidation by the oxidation products of CO (namely, adsorbed CO 2 or CO 2 adsorption products with co-adsorbed species such as H ads to form COOH ads [44, 45]). Because CO oxidation is generally agreed to follow a Langmuir-Hinshelwood reaction mechanism [44, 46], impedance to its adsorption to the working electrode surface will impede its oxidation. This hypothesis requires further investigation to fully confirm.…”

Section: Resultsmentioning

confidence: 99%

Highly sensitive amperometric Pt–Nafion gas phase nitric oxide sensor: Performance and application in characterizing nitric oxide-releasing biomaterials

Zhang

Ren

VonWald

et al. 2015

Analytica Chimica Acta

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A highly sensitive amperometric gas-phase nitric oxide (NO) sensor based on a Pt working electrode chemically deposited on a Nafion film is described. The Pt electrode is chemically deposited on a Nafion 117 membrane by impregnating the film with Pt(NH3)42+ ions, which are then exposed to NaBH4 to precipitate conductive Pt metal. The sensor was characterized with a mass-flow controlled 1 ppm NO standard gas and has an electrochemical surface area of 34 ± 9 cm2, low limits of detection (4.3 ± 1.1 ppb) and a fast response time (<5s) toward changes in gas phase NO levels. Good correlation was found for measurements with the new amperometric Pt-Nafion sensor vs. chemiluminescence results for detecting the rates of NO released from CarboSil 2080A polymer films doped with S-nitroso-N-acetylpenicillamine (R = 0.999, m = 0.999, n = 6) and for electrochemical reduction of nitrite to NO (R = 0.999, m = 0.938, n = 3) mediated by a copper(II)-tri(2-pyridylmethyl)amine complex.

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Kinetic study of CO oxidation on clean and oxidized Pt

Cited by 12 publications

References 52 publications

Operando Surface Studies on Metal-Oxide Interfaces of Bimetal and Mixed Catalysts

Operando Surface Studies on Metal-Oxide Interfaces of Bimetal and Mixed Catalysts

Electrochemical Nitric Oxide Sensors: Principles of Design and Characterization

Highly sensitive amperometric Pt–Nafion gas phase nitric oxide sensor: Performance and application in characterizing nitric oxide-releasing biomaterials

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