Surface reactions of sulfur with oxygen on Pt(111)

Köhler, Ulrich; Wassmuth, H.-W.

doi:10.1016/0039-6028(82)90547-7

Cited by 54 publications

(17 citation statements)

References 15 publications

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“…Studies of sulfur oxidation on Pt consistently find that it proceeds by a Langmuir-Hinshelwood reaction between adsorbed S and SO and adsorbed oxygen atoms; dissociative adsorption of oxygen from the gas phase is therefore an essential first step in the reaction. 43,[46][47][48][49][50][51] Even low coverages of sulfur strongly suppress the adsorption of oxygen, 31,43,46,47 resulting in a strong suppression of the oxidation reaction with increasing sulfur coverage similar to the behavior we observe in Fig. 9.…”

Section: Discussionsupporting

confidence: 79%

Sulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensor

Kahng

Tobin

Loloee

et al. 2007

Journal of Applied Physics

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We have investigated the effects of sulfur contamination on a Pt-gate silicon carbide based field-effect gas sensor, under ultrahigh vacuum conditions, at a temperature of 527°C. Exposure to hydrogen sulfide, even in the presence of hydrogen or oxygen at partial pressures of 20-600 times greater than the H 2 S level, rapidly coated the gate with a monolayer of sulfur. Sulfur contamination reduced the magnitude of the sensor's response to alternating hydrogen and oxygen pulses by about 70%, as compared to the uncontaminated gate. There was no evidence of irreversible changes in device behavior due to sulfur deposition and removal. The adsorbed sulfur could not be removed by exposure to hydrogen at the pressures accessible. Oxygen was effective at removing the sulfur. The rate of sulfur oxidation was suppressed at high sulfur coverages, but not as strongly as on low-index single-crystal surfaces. These results are discussed in the context of prior experiments on Pt crystals and films.

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Section: Discussionsupporting

confidence: 79%

Sulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensor

Kahng

Tobin

Loloee

et al. 2007

Journal of Applied Physics

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“…Wassmuth et al concluded that SO2 adsorbs dissociatively at 160 K forming SOa and Oa, which undergo recombinative desorption at 300 K [22,23,24]. In the light of their HREELS and XPS data, White et al [16] argue in favour of molecular adsorption at 130 K, followed at 300 K either by desorption as SO2, or dissociation to form adsorbed S, SO and SO4.…”

Section: Discussionmentioning

confidence: 99%

Short-Chain Alkane Activation

Wilson

Hardacre

Lambert

1996

ACS Symposium Series

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SO 2 chemisorption on oxygenated Pt(111) enormously enhances the dissociative chemisorption and subsequent combustion of propane. This activation of the metal surface is induced by an adsorbed sulfoxy species which is formed > 220 K. In the absence of adsorbed SO 2 the sticking probability of propane is immeasurably small. However in the presence of SO 2 , the precursor-mediated initial sticking probability rises from ~0.02 at 300 K to ~ 0.15 at 160 K. XPS and HREELS measurements identify the active species as SO4 2-, and also demonstrate the consumption of SO 4 during the oxidation reaction. Coincident CO 2 and SO 2 formation suggest decomposition of a complex reaction intermediate: this is supported by isotope experiments involving CO adsorption onto SO 2 / 18 O2 precovered Pt(111). Propane oxidation over sulphated AlO X films on Pt (111) is also reported, with increased activity for submonolayer oxidised Al films being observed compared to clean Pt(111).The activation of short chain alkanes is often the rate limiting step in catalytic oxidation of hydrocarbons [1]. In particular, the slow oxidation of alkanes, namely propane and methane, is a technological problem faced by the automotive exhaust catalyst industry [2]. Reactor studies of Pt/Al203 and Pt-Rh/Al203/Ce02 catalysts have shown that the inclusion of SO2 in the gas feed significantly promotes the oxidation of propane [3,4], whilst inhibiting reactions of CO, NO and propene. It has also been observed that in the presence of SO2, the activity of Pt/Al203 catalysts for propane oxidation becomes independent of Pt loading. In the absence of SO2, the activity usually increases with Pt loading, a result which suggests the formation of different active sites on inclusion of SO2 in the gas feed. Infra-red analysis of these catalysts following exposure to O2 and SO2, indicates the presence of S04^" on the support, which is thought to be involved in the activation process. Enhanced C-H bond dissociation is often attributed to catalyst acidity [5]; for example homogeneous Pt(III) solutions display increased oxidative capacity in the presence of sulphuric acid.

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“…According to Figure 12.c, it can be deduced that sulfur is present in a single form and a single type of sulfate S 6+ [52][53][54][55] in the surface structure of the poisoned Pt/Al catalyst, as shown by the presence of a single transition S2p1/2 and of S2p3/2. Thus, based on the XPS results, it can be concluded that the accelerated aging had affected the surface of the Pt/Al catalyst in the similar way than the industrial ageing in terms of sulfur interaction.…”

Section: Activity and Characterization Of The Fresh And Industrially mentioning

confidence: 99%

“…To get more compound-specific information on the poisoning of 0.3Pt10Cu/Al and 0.3Pt10Cu/AlSi20 catalysts, XPS measurements were carried out for fresh and poisoned samples. According to the decomposition of the individual components of S 2p ( Figures 18.a and b), the binding energy of the S 2p1/2 at 168.9 eV, showed that sulfur is present only in the form of S 6+ [52][53][54][55], as proved by the presence of a single transition of S 2p1/2 and S 2p3/2 in both the cases. After carrying out the accelerated laboratory ageing on 0.3Pt10Cu/Al and 0.3Pt10Cu/AlSi20…”

Section: Sulfur Poisoning Of Bimetallic Catalystsmentioning

confidence: 99%

Study on sulfur deactivation of catalysts for DMDS oxidation

Darif

Ojala

Kärkkäinen

et al. 2017

Applied Catalysis B: Environmental

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In the present research, an industrially aged Pt/Al2O3 catalyst was used as a basis for the study on the sulfur deactivation and the development of more resistant catalytic materials. The catalytic activities of both industrially and laboratory-aged materials in DMDS oxidation were studied in addition to characterization by XRD, XPS, FESEM, TEM and N2 adsorption. The industrial ageing induced a phase change from γ-Al2O3 towards θ-Al2O3, formation of aluminum sulfates and an increase in Pt particle size as well as a change in the oxidation state of Pt to a higher state. These changes caused an increase of 30°C in the light-off temperature for DMDS oxidation. Accelerated ageing in the presence of SO2 and H2O vapor at 400°C for 5 h decreased the activity of the Pt/Al2O3 at the same level than for the industrially aged catalyst even though smaller sulfur content and no sintering of γ-Al2O3 were observed. Pt sintering (10-20 nm) in both cases was observed. The XPS results confirmed the formation of new sulfate phases and the interaction between sulfur and the active phase as well as the support of the catalyst undergone accelerated ageing. After the accelerated ageing of copper-based catalysts, the 0.3Pt10Cu/Al2O3|0.8SiO2|0.2 catalyst showed an interesting resistance towards sulfur deactivation, as it was expected.

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Surface reactions of sulfur with oxygen on Pt(111)

Cited by 54 publications

References 15 publications

Sulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensor

Sulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensor

Short-Chain Alkane Activation

Study on sulfur deactivation of catalysts for DMDS oxidation

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