Discrete catalytic sites for quinone in the ubiquinol-cytochrome c2 oxidoreductase of Rhodopseudomonas capsulata. Evidence from a mutant defective in ubiquinol oxidation.

AbstractThe heterogeneous catalyst HTCMgFe was used in the degradation of the IC, through the heterogeneous photo-fenton treatment, this material in combination with H2O2 and UV light degraded the dye in 30 min at pH 3. As the amount of HTCMgFe increases the degradation it was accelerated because there are more active catalytic sites of Fe2+ on the surface of the material, which generates a greater amount of •OH radicals. The HTCMgFe was characterized by infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray energy dispersive elemental analysis (EDS). The UV-vis spectrum shows that the absorption bands belonging to the chromophore group of the IC disappear as the treatment time passes, indicating the degradation of the dye.

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Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst

10.26434/chemrxiv.12346823.v3 ◽

2020 ◽

Author(s):

hao yin ◽

Liqing Zheng ◽

Wei Fang ◽

Yin-Hung Lai ◽

Nikolaus Porenta ◽

...

Keyword(s):

Catalytic Hydrogenation ◽

Density Functional ◽

Hydrogen Transfer ◽

Bimetallic Catalyst ◽

Local Environment ◽

Hydrogenation Reaction ◽

Boundary Density ◽

Catalytic Sites ◽

Powerful Analytical Tool ◽

Tip Enhanced Raman Spectroscopy

Understanding the mechanism of catalytic hydrogenation at the local environment requires chemical and topographic information involving catalytic sites, active hydrogen species and their spatial distribution. Here, tip-enhanced Raman spectroscopy (TERS) was employed to study the catalytic hydrogenation of chloro-nitrobenzenethiol on a well-defined Pd(sub-monolayer)/Au(111) bimetallic catalyst (pH2=1.5 bar, 298 K), where the surface topography and chemical fingerprint information were simultaneously mapped with nanoscale resolution (≈10 nm). TERS imaging of the surface after catalytic hydrogenation confirms that the reaction occurs beyond the location of Pd sites. The results demonstrate that hydrogen spillover accelerates hydrogenation at the Au sites within 20 nm from the bimetallic Pd/Au boundary. Density functional theory was used to elucidate the thermodynamics of interfacial hydrogen transfer. We demonstrate that TERS as a powerful analytical tool provides a unique approach to spatially investigate the local structure-reactivity relationship in catalysis.

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Nanometer Scale Spectroscopic Visualization of Catalytic Sites During a Hydrogenation Reaction on a Pd/Au Bimetallic Catalyst

10.26434/chemrxiv.12346823.v1 ◽

2020 ◽

Author(s):

Hao Yin ◽

Liqing Zheng ◽

Wei Fang ◽

Yin-Hung Lai ◽

Nikolaus Porenta ◽

...

Keyword(s):

Catalytic Hydrogenation ◽

Density Functional ◽

Hydrogen Transfer ◽

Bimetallic Catalyst ◽

Local Environment ◽

Hydrogenation Reaction ◽

Boundary Density ◽

Catalytic Sites ◽

Powerful Analytical Tool ◽

Tip Enhanced Raman Spectroscopy

Understanding the mechanism of catalytic hydrogenation at the local environment requires chemical and topographic information involving catalytic sites, active hydrogen species and their spatial distribution. Here, tip-enhanced Raman spectroscopy (TERS) was employed to study the catalytic hydrogenation of chloro-nitrobenzenethiol on a well-defined Pd(sub-monolayer)/Au(111) bimetallic catalyst (pH2=1.5 bar, 298 K), where the surface topography and chemical fingerprint information were simultaneously mapped with nanoscale resolution (≈10 nm). TERS imaging of the surface after catalytic hydrogenation confirms that the reaction occurs beyond the location of Pd sites. The results demonstrate that hydrogen spillover accelerates hydrogenation at the Au sites within 20 nm from the bimetallic Pd/Au boundary. Density functional theory was used to elucidate the thermodynamics of interfacial hydrogen transfer. We demonstrate that TERS as a powerful analytical tool provides a unique approach to spatially investigate the local structure-reactivity relationship in catalysis.

Download Full-text