scholarly journals METHANE LIQUEFACTION: Selective Conversion of Methane to Cyclohexane via Efficient Surface-Hydrogen-Transfer Catalyzed by GaN-Supported Platinum Clusters

2021 ◽  
Author(s):  
Li-Da Tan ◽  
Hui Su ◽  
Jingtan Han ◽  
Mingxin Li ◽  
Chao-Jun Li
Keyword(s):  
Hydrogen Transfer ◽  
Ambient Pressure ◽  
Chemical Research ◽  
Methane Aromatization ◽  
Surface Hydrogen ◽  
Platinum Cluster ◽  
Supported Platinum ◽  
Conversion Of Methane ◽  
Platinum Clusters

Abstract Non-oxidative liquefaction of methane at room temperature and ambient pressure has long been a scientific “holy grail” of chemical research. In this report, we exploit an unprecedented catalytic transformation of methane exclusively to cyclohexane through effective surface-hydrogen-transfer (SHT) at the heterojunctions boundary consisting of electron-rich platinum cluster (Pt) loaded on methane-activating gallium nitride (GaN) host. The experimental analysis demonstrates that interface-induced overall reaction starts with methane aromatization to benzene initiated by the Ga-N pairs, followed by hydrogenation of benzene to cyclohexane via hydrogen transfer. The in-situ activated hydrogen at electron-rich metal Pt cluster plays a key role for the hydrogenation and enables an outstanding selectivity (as high as 89 %) towards cyclohexane, which is well-delivered even after 5 recycling runs.

Thermal Stability of Supported Platinum Clusters Studied by in Situ GISAXS

2004 ◽  
Vol 108 (47) ◽  
pp. 18105-18107 ◽  
Author(s):  
Randall E. Winans ◽  
Stefan Vajda ◽  
Byeongdu Lee ◽  
Stephen J. Riley ◽  
Sönke Seifert ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Supported Platinum ◽  
Platinum Clusters ◽  
Thermal Stability Of

The Electronic Interaction of Pt-Clusters with ITO and HOPG Surfaces upon Water Adsorption

2014 ◽  
Vol 228 (4-5) ◽  
Author(s):  
Joachim Klett ◽  
Stephan Krähling ◽  
Benjamin Elger ◽  
Rolf Schäfer ◽  
Bernhard Kaiser ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Efficiency ◽  
Catalytic Performance ◽  
Substrate Material ◽  
Binding Energies ◽  
Electronic Interaction ◽  
Support Materials ◽  
Platinum Cluster ◽  
Supported Platinum ◽  
Platinum Clusters

AbstractIn order to investigate the catalytic properties of supported platinum clusters, their interaction with water was monitored using photoelectron spectroscopy. The clusters were exposed to up to five Langmuir of water at cryogenic temperatures. Additionally, the influence of the substrate was studied by employing HOPG and ITO as complementary support materials. In contrast to bulk platinum a distinct chemical shift is observable in the Pt4f binding energies for Pt clusters deposited on ITO. The same clusters on HOPG show no changes in binding energy. We propose that this trend is due to a change in the surface Fermi level in ITO, hence highlighting the strong interaction between the platinum cluster and the substrate material. Therefore it is reasonable to assume, that the catalytic efficiency of these clusters in general can not solely be described by the electronic structure of the cluster alone, but that also the electronic changes induced in the substrate may have a major impact on the catalytic performance as well.

scholarly journals Copper-Modified Zeolites and Silica for Conversion of Methane to Methanol

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 545 ◽  
Author(s):  
Xueting Wang ◽  
Natalia Martin ◽  
Johan Nilsson ◽  
Stefan Carlson ◽  
Johan Gustafson ◽  
...  
Keyword(s):  
Active Sites ◽  
Copper Ions ◽  
Ambient Pressure ◽  
Direct Conversion ◽  
Minor Amount ◽  
Powder Materials ◽  
Methanol Production ◽  
Conversion Of Methane ◽  
First Time

Powder materials containing copper ions supported on ZSM-5 (Cu-Zeolite Socony Mobil-5) and SSZ-13 (Cu-Standard Oil synthesised zeolite-13), and predominantly CuO nanoparticles on amorphous SiO 2 were synthesised, characterised, wash-coated onto ceramic monoliths and, for the first time, compared as catalysts for direct conversion of methane to methanol (DCMM) at ambient pressure (1 atm) using O 2 , N 2 O and NO as oxidants. Methanol production was monitored and quantified using Fourier transform infrared spectroscopy. Methanol is formed over all monolith samples, though the formation is considerably higher for the copper-exchanged zeolites. Hence, copper ions are the main active sites for DCMM. The minor amount of methanol produced over the Cu/SiO 2 sample, however, suggests that zeolites are not the sole substrate that can host those active copper sites but also silica. Further, we present the first ambient pressure in situ infrared spectroscopic measurements revealing the formation and consumption of surface methoxy species, which are considered to be key intermediates in the DCMM reaction.

In Situ XAS Investigation of Transformation of Co Monolayer on Carbon-Supported Platinum Clusters Underpotential Control

2004 ◽  
Vol 108 (39) ◽  
pp. 15096-15102 ◽  
Author(s):  
B. J. Hwang ◽  
Y. W. Tsai ◽  
Loka S. Sarma ◽  
C. H. Chen ◽  
J.-F. Lee ◽  
...  
Keyword(s):  
Supported Platinum ◽  
In Situ Xas ◽  
Platinum Clusters

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

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