Interactions of SO2 and H2S with amorphous carbon films

Michalak, William D.; Broitman, Esteban; Maryanne, Alvin,; Gellman, Andrew J.; Miller, James B.

doi:10.1016/j.apcata.2009.04.008

Cited by 14 publications

(9 citation statements)

References 29 publications

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“…It was observed that when the gas was shifted from dry air to nitrogen, a shift in transfer curve was observed. As theoretical studies predict very weak adsorp- tion of H 2 S on graphitic structures at room temperature [31], and based on our above-observed results, we conclude that the observed "shift" is mainly caused by the displacement of oxygen molecules. By contrast, gold decorated SWNTs show both "shift" and "tilt" in their FET transfer curve after exposure to low concentrations (2-100 ppb V ) of H 2 S. The observed shift is caused by Schottky barrier mechanism [32] where adsorbed gas molecules at metal-nanotube contact alter the work function of the metal and thereby change the band alignment resulting in carrier scattering and decreased hole mobility.…”

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confidence: 61%

Gas Sensing Mechanism of Gold Nanoparticles Decorated Single‐Walled Carbon Nanotubes

et al. 2011

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Metal nanoparticles decorated single-walled carbon nanotubes (SWNTs) can lead to considerable enhancement in sensing performance towards different gas analytes, however the sensing mechanism was not clearly elucidated. The detailed sensing mechanism of hybrid gold-SWNT nanostructures toward hydrogen sulfide was investigated using field effect transistor (FET) transfer characteristics. At low H 2 S concentrations ( 100 ppb V ), FET transfer characteristics show that the gold nanoparticles at the surface of SWNTs acted as nano-Schottky barriers to predominately modulate transconductance upon exposure to unfunctionalized SWNTs on gold electrodes which showed little or no response upon exposure. Although the sensitivity of Au/SWNT toward H 2 S was strongly dependent upon the size and number of gold nanoparticles, the sensing mechanism was independent of it.

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confidence: 61%

Gas Sensing Mechanism of Gold Nanoparticles Decorated Single‐Walled Carbon Nanotubes

et al. 2011

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“…Pd 4 S and Pd 70 Cu 30 (H 2 S) display identical values of ΔH H2S (−0.21 eV) and ΔS H2S (−10 −3.15 eV/K). This value of ΔH H2S is in the range of those observed for nondissociative H 2 S adsorption on relatively inert surfaces, such as carbons, 29 suggesting that H 2 S is not strongly bound to the surface sulfide. S and with 9 mL/min each of H 2 and D 2 in the feed gas.…”

Section: H 2 -D 2 Exchange Over Pd 47mentioning

confidence: 77%

H₂-D₂ Exchange Kinetics in the Presence of H₂S over Pd₄S, Pd₇₀Cu₃₀, and Pd₄₇Cu₅₃ Surfaces

et al. 2012

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H 2 S retards H 2 transport across Pd membranes used for H 2 separation by forming a Pd 4 S scale that has both low H 2 dissociation activity and low H-atom permeability. As hydrogen purification membranes, alloys such as Pd 70 Cu 30 and Pd 47 Cu 53 are attractive alternatives to pure Pd due to their resistance to formation of bulk sulfides. Nonetheless, exposure to H 2 S can decrease the permeability of Pd 70 Cu 30 and Pd 47 Cu 53 membranes, presumably by poisoning the catalytic activity of their surfaces for H 2 dissociation. In this work, the effect of H 2 S on H 2 dissociation on Pd 4 S, Pd 70 Cu 30 , and Pd 47 Cu 53 surfaces is investigated by microkinetic analysis of H 2 -D 2 exchange kinetics over Pd 4 S, Pd 70 Cu 30 , and Pd 47 Cu 53 surfaces in the presence of varying concentrations of H 2 S at nearambient H 2 +D 2 pressure. We show that the rate of H 2 -D 2 exchange over all three surfaces is significantly suppressed when H 2 S is added to H 2 /D 2 /Ar reactant mixtures and that the suppression of H 2 -D 2 exchange increases with increasing H 2 S concentration. Microkinetic analysis of the H 2 -D 2 exchange kinetics reveals that H 2 S decreases the rate of H 2 -D 2 exchange by two distinct mechanisms: (1) increasing the intrinsic barrier to H 2 dissociation and (2) blocking H 2 dissociation sites.

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“…13 HOPG was observed to be unreactive toward H 2 S dissociation at UHV, however. 14 Also, preparation techniques used for those flakes can lead to hard to detect (metal) impurities. 15 In addition, in the solution phase, Gr flakes are often functionalized (e.g., to Gr oxide).…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Small Sulfur Compounds (H₂S and SO₂) on SiO₂ Supported Graphene–the Quest for a Metal-Free Catalyst–Experiment and Theory

Stach,

Seif,

Ambrosetti

et al. 2024

J. Phys. Chem. C

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The adsorption of hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) was studied at ultrahigh vacuum conditions on silica (SiO 2 ) supported graphene, in order to characterize a potentially metal-free catalyst. However, kinetics experiments (using thermal desorption spectroscopy) and spectroscopy (Auger electron spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy) revealed only molecular adsorption. Density functional theory (DFT) also obtained large activation energies for dissociation. The low reactivity contrasts with previously studied graphene on ruthenium [Stach, T. et al.

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Interactions of SO2 and H2S with amorphous carbon films

Cited by 14 publications

References 29 publications

Gas Sensing Mechanism of Gold Nanoparticles Decorated Single‐Walled Carbon Nanotubes

Gas Sensing Mechanism of Gold Nanoparticles Decorated Single‐Walled Carbon Nanotubes

H₂-D₂ Exchange Kinetics in the Presence of H₂S over Pd₄S, Pd₇₀Cu₃₀, and Pd₄₇Cu₅₃ Surfaces

Adsorption of Small Sulfur Compounds (H₂S and SO₂) on SiO₂ Supported Graphene–the Quest for a Metal-Free Catalyst–Experiment and Theory

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Interactions of SO2 and H2S with amorphous carbon films

Cited by 14 publications

References 29 publications

Gas Sensing Mechanism of Gold Nanoparticles Decorated Single‐Walled Carbon Nanotubes

Gas Sensing Mechanism of Gold Nanoparticles Decorated Single‐Walled Carbon Nanotubes

H2-D2 Exchange Kinetics in the Presence of H2S over Pd4S, Pd70Cu30, and Pd47Cu53 Surfaces

Adsorption of Small Sulfur Compounds (H2S and SO2) on SiO2 Supported Graphene–the Quest for a Metal-Free Catalyst–Experiment and Theory

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H₂-D₂ Exchange Kinetics in the Presence of H₂S over Pd₄S, Pd₇₀Cu₃₀, and Pd₄₇Cu₅₃ Surfaces

Adsorption of Small Sulfur Compounds (H₂S and SO₂) on SiO₂ Supported Graphene–the Quest for a Metal-Free Catalyst–Experiment and Theory