Rücktitelbild: Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY (Angew. Chem. 24/2012)

2012 ◽  
Vol 124 (24) ◽  
pp. 6120-6120
Author(s):  
Jing Lu ◽  
Ceren Aydin ◽  
Nigel D. Browning ◽  
Bruce C. Gates
Keyword(s):  
Gold Atom ◽  
Zeolite Nay ◽  
Catalytic Sites

Back Cover: Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY (Angew. Chem. Int. Ed. 24/2012)

2012 ◽  
Vol 51 (24) ◽  
pp. 6016-6016
Author(s):  
Jing Lu ◽  
Ceren Aydin ◽  
Nigel D. Browning ◽  
Bruce C. Gates
Keyword(s):  
Gold Atom ◽  
Zeolite Nay ◽  
Back Cover ◽  
Catalytic Sites

Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY

2012 ◽  
Vol 51 (24) ◽  
pp. 5842-5846 ◽  
Author(s):  
Jing Lu ◽  
Ceren Aydin ◽  
Nigel D. Browning ◽  
Bruce C. Gates
Keyword(s):  
Gold Atom ◽  
Zeolite Nay ◽  
Catalytic Sites

Imaging Isolated Gold Atom Catalytic Sites in Zeolite NaY

2012 ◽  
Vol 124 (24) ◽  
pp. 5944-5948 ◽  
Author(s):  
Jing Lu ◽  
Ceren Aydin ◽  
Nigel D. Browning ◽  
Bruce C. Gates
Keyword(s):  
Gold Atom ◽  
Zeolite Nay ◽  
Catalytic Sites

Synthesis of HTCMgFe for the degradation of indigo carmine through heterogeneous photo-Fenton treatment

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3273-3282
Author(s):  
I. Cosme-Torres ◽  
M.G. Macedo-Miranda ◽  
S.M. Martinez-Gallegos ◽  
J.C. González-Juárez ◽  
G. Roa-Morales ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Treatment Time ◽  
Uv Light ◽  
Indigo Carmine ◽  
Oh Radicals ◽  
Absorption Bands ◽  
Chromophore Group ◽  
X Ray ◽  
Catalytic Sites ◽  
Scanning Electron

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.

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

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

<p>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 (<i>p</i><sub>H2</sub>=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.</p>

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

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

<p>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 (<i>p</i><sub>H2</sub>=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.</p>

Explaining the magnetism of gold

2017 ◽  
Author(s):  
Robson de Farias
Keyword(s):  
Gas Phase ◽  
Computational Study ◽  
Formation Enthalpy ◽  
Gold Atom ◽  
Orbital Energy ◽  
Knudsen Effusion ◽  
Energy Diagram ◽  
Unpaired Electrons ◽  
The Difference ◽  
Good Agreement

<p>In the present work, a computational study is performed in order to clarify the possible magnetic nature of gold. For such purpose, gas phase Au<sub>2</sub> (zero charge) is modelled, in order to calculate its gas phase formation enthalpy. The calculated values were compared with the experimental value obtained by means of Knudsen effusion mass spectrometric studies [5]. Based on the obtained formation enthalpy values for Au<sub>2</sub>, the compound with two unpaired electrons is the most probable one. The calculated ionization energy of modelled Au<sub>2</sub> with two unpaired electrons is 8.94 eV and with zero unpaired electrons, 11.42 eV. The difference (11.42-8.94 = 2.48 eV = 239.29 kJmol<sup>-1</sup>), is in very good agreement with the experimental value of 226.2 ± 0.5 kJmol<sup>-1</sup> to the Au-Au bond<sup>7</sup>. So, as expected, in the specie with none unpaired electrons, the two 6s<sup>1</sup> (one of each gold atom) are paired, forming a chemical bond with bond order 1. On the other hand, in Au<sub>2</sub> with two unpaired electrons, the s-d hybridization prevails, because the relativistic contributions. A molecular orbital energy diagram for gas phase Au<sub>2</sub> is proposed, explaining its paramagnetism (and, by extension, the paramagnetism of gold clusters and nanoparticles).</p>

Dissolution and Performing Homogeneous Photocatalysis of Polymeric Carbon Nitride

2018 ◽  
Author(s):  
Chaofeng Huang ◽  
Jing Wen ◽  
Yanfei Shen ◽  
Fei He ◽  
Li Mi ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Carbon Nitride ◽  
Heterogeneous Catalysts ◽  
Methane Sulfonic Acid ◽  
Environment Friendly ◽  
The Poor ◽  
Catalytic Sites ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

<a></a><a>As a metal-free conjugated polymer, carbon nitride (CN) has attracted tremendous attention as heterogeneous (photo)catalysts. </a><a></a><a>By following prototype of enzymes, making all catalytic sites of accessible via homogeneous reactions is a promising approach toward maximizing CN activity, but hindered due to </a><a></a><a>the poor insolubility of CN</a>. Herein, we report the dissolution of CN in environment-friendly methane sulfonic acid and the homogeneous photocatalysis driven by CN for the first time with the activity boosted up to 10-times, comparing to the heterogeneous counterparts. Moreover, facile recycling and reusability, the <a>hallmark</a> of heterogeneous catalysts, were kept for the homogeneous CN photocatalyst via reversible precipitation using poor solvents. It opens new vista of CN in homogeneous catalysis and offers a successful example of polymeric catalysts in bridging gaps of homo/heterogeneous catalysis.

Sign in / Sign up

Export Citation Format

Share Document