scholarly journals Isolated Single-Atomic Cu Catalyst Supported on P-doped Carbon for Hydrochlorination of Acetylene

2021 ◽  
Author(s):  
Ting Wang ◽  
Zhao Jiang ◽  
Qi Tang ◽  
Bolin Wang ◽  
Saisai Wang ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Carbon Support ◽  
Impregnation Method ◽  
Phosphorus Doping ◽  
Phosphorus Species ◽  
Acetylene Hydrochlorination ◽  
Copper Species ◽  
Phosphorus Doped

Abstract As an environmentally friendly non-mercury catalyst for the hydrochlorination of acetylene, Cu-based catalysts have always attracted attention. In this study, a series of phosphorus-doped Cu-based catalysts supported on activated carbon were prepared by the wet impregnation method, the difference of them is that the calcination temperature of phosphorus-doped carrier is 200 ℃, 400 ℃, 600 ℃ and 800 ℃ respectively. In the test conditions of T = 150℃, GHSV(C2H2) = 90 h− 1 and V(HCl): V(C2H2) = 1.2, the highest acetylene conversion was 83.1%. The type of phosphorus configuration and the distribution on the surface of the carrier can be adjusted by changing the calcination temperature. Among the different phosphorus species formed by the phosphorus doping treatment at different temperatures, the P-C bond formed after the phosphorus element is incorporated into the carbon lattice also accounts for an increasing proportion with the increase of the calcination temperature,which is accompanied by a higher and higher acetylene conversion. It can be seen that the P-C bond plays a key role in the acetylene hydrochlorination reaction in this system. Meanwhile, Cu2+ was identified as the main active component in the catalyst by XPS. The representative HAADF-STEM image shows isolated copper species, confirming that the single-center copper species supported on the carbon support is the active center of the acetylene hydrochlorination reaction. The coordination structure formed by the interaction between the P-C bond and the atomically dispersed Cu2+ species is an effective and stable active site in the reaction. Density functional theory calculations indicate that the reaction is proposed to proceed according to the Langmuir-Hinshelwood (L-H) mechanism. This work is the first to identify which phosphorus species plays a role in the hydrochlorination of acetylene, which may provide some ideas for the design and optimization of phosphorus doping catalysts in the future.

Hydrochlorination of acetylene using supported phosphorus-doped Cu-based catalysts

2015 ◽  
Vol 5 (12) ◽  
pp. 5174-5184 ◽  
Author(s):  
Hang Li ◽  
Fumin Wang ◽  
Wangfeng Cai ◽  
Jinli Zhang ◽  
Xubin Zhang
Keyword(s):  
Phosphorus Doping ◽  
Acetylene Hydrochlorination ◽  
Copper Species ◽  
Phosphorus Doped

Phosphorus doping facilitates the dispersion of copper species, enhances the interaction between metal and support, and restrains the growth of copper components during acetylene hydrochlorination.

scholarly journals Interactions between atomically dispersed copper and phosphorous species are key for the hydrochlorination of acetylene

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Ting Wang ◽  
Zhao Jiang ◽  
Qi Tang ◽  
Bolin Wang ◽  
Saisai Wang ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Vinyl Chloride ◽  
Active Sites ◽  
Low Cost ◽  
Mercury Chloride ◽  
Phosphorus Species ◽  
Acetylene Hydrochlorination ◽  
Design And Optimization ◽  
Green Production ◽  
Phosphorus Doped

AbstractVinyl chloride, the monomer of polyvinyl chloride (PVC), is industrially synthesized via acetylene hydrochlorination. Thereby, easy to sublimate but toxic mercury chloride catalysts are widely used. It is imperative to find environmentally friendly non-mercury catalysts to promote the green production of PVC. Low-cost copper-based catalysts are promising candidates. In this study, phosphorus-doped Cu-based catalysts are prepared. It is shown that the type of phosphorus configuration and the distribution on the surface of the carrier can be adjusted by changing the calcination temperature. Among the different phosphorus species, the formed P-C bond plays a key role. The coordination structure formed by the interaction between P-C bonds and atomically dispersed Cu2+ species results in effective and stable active sites. Insights on how P-C bonds activate the substrate may provide ideas for the design and optimization of phosphorus-doped catalysts for acetylene hydrochlorination.

Synthesis and properties of ladder-type 1,4-dihydro-1,4-phosphasilins

2009 ◽  
Vol 87 (9) ◽  
pp. 1222-1229 ◽  
Author(s):  
Yi Ren ◽  
Thomas Linder ◽  
Thomas Baumgartner
Keyword(s):  
Density Functional ◽  
Small Deviation ◽  
Density Functional Theory Calculations ◽  
Advanced Characterization ◽  
Building Blocks ◽  
Structural Features ◽  
Structure Property ◽  
Electronic Effects ◽  
Phosphorus Species ◽  
Molecular Scaffold

The synthesis and advanced characterization of a series of extended dithieno[2,3-b:3′,2′-e][1,4-dihydro-1,4]phosphasilins is reported, and their suitability as new building blocks for organic electronics is evaluated. Synthesis of basic, as well as benzo-extended dithienophosphasilins, can be achieved using appropriate 2,3-dibromothiophene precursors in a two-step protocol introducing the silicon and phosphorus centers subsequently. Both ladder-type materials show the typical reactivity of trivalent phosphorus species and can quantitatively be converted into the corresponding oxides or gold complexes, the latter exemplified with the basic dithienophosphasilin. Their optoelectronic properties were found to be inferior to those of related dithieno[3,2-b:2′,3′-d]phospholes, indicating a disruption of the π-conjugation in the molecular scaffold. X-ray crystallographic studies revealed that the molecular scaffold is planar in the oxidized benzo-extended material, whereas the basic dithieno materials show some small deviation from planarity. Density functional theory calculations suggest all materials to be planar, with the exception of the benzo-extended trivalent phosphasilin. This structure–property study illustrates that the disruption of the π-conjugation in the molecular scaffold of the extended phosphasilins is exclusively due to the presence of the silicon center and its electronic effects, rather than structural features.

C-doped boron nitride fullerene as a novel catalyst for acetylene hydrochlorination: a DFT study

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 56348-56355 ◽  
Author(s):  
Fei Zhao ◽  
Yang Wang ◽  
Mingyuan Zhu ◽  
Lihua Kang
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Dft Study ◽  
Functional Theory ◽  
Acetylene Hydrochlorination ◽  
Carbon Doped ◽  
Novel Catalyst

Density functional theory calculations were used to investigate the mechanism of acetylene hydrochlorination separately catalyzed by un-doped B12N12 and carbon-doped BN fullerene (B12−nN11+nC (n = 0, 1)).

Field Effect Modulation of Electrocatalytic Hydrogen Evolution at Back-Gated Two-Dimensional MoS2 Electrodes

2019 ◽  
Author(s):  
Yan Wang ◽  
Sagar Udyavara ◽  
Matthew Neurock ◽  
C. Daniel Frisbie
Keyword(s):  
Electric Field ◽  
Hydrogen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Electrode Materials ◽  
Density Functional Theory Calculations ◽  
Electronic Charge ◽  
Back Side ◽  
Gate Electrode ◽  
Conventional Manner

<div> <div> <div> <p> </p><div> <div> <div> <p>Electrocatalytic activity for hydrogen evolution at monolayer MoS2 electrodes can be enhanced by the application of an electric field normal to the electrode plane. The electric field is produced by a gate electrode lying underneath the MoS2 and separated from it by a dielectric. Application of a voltage to the back-side gate electrode while sweeping the MoS2 electrochemical potential in a conventional manner in 0.5 M H2SO4 results in up to a 140-mV reduction in overpotential for hydrogen evolution at current densities of 50 mA/cm2. Tafel analysis indicates that the exchange current density is correspondingly improved by a factor of 4 to 0.1 mA/cm2 as gate voltage is increased. Density functional theory calculations support a mechanism in which the higher hydrogen evolution activity is caused by gate-induced electronic charge on Mo metal centers adjacent the S vacancies (the active sites), leading to enhanced Mo-H bond strengths. Overall, our findings indicate that the back-gated working electrode architecture is a convenient and versatile platform for investigating the connection between tunable electronic charge at active sites and overpotential for electrocatalytic processes on ultrathin electrode materials.</p></div></div></div><br><p></p></div></div></div>

A New Phase of the Na+ Ion Conductor Na3PS4

2019 ◽  
Author(s):  
Theodosios Famprikis ◽  
James Dawson ◽  
François Fauth ◽  
Emmanuelle Suard ◽  
Benoit Fleutot ◽  
...  
Keyword(s):  
Solid Electrolytes ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Ion Conductor ◽  
Solid State Batteries ◽  
Density Analysis ◽  
Two Phases ◽  
Dynamics Simulations

<div> <p>Solid electrolytes are crucial for next‑generation solid‑state batteries and Na<sub>3</sub>PS<sub>4</sub> is one of the most promising Na<sup>+</sup> conductors for such applications. At present, two phases of Na<sub>3</sub>PS<sub>4</sub> have been identified and it had been thought to melt above 500 °C. In contrast, we show that it remains solid above this temperature and transforms into a third polymorph, γ, exhibiting superionic behavior. We propose an orthorhombic crystal structure for γ‑Na<sub>3</sub>PS<sub>4</sub> based on scattering density analysis of diffraction data and density functional theory calculations. We show that the Na<sup>+</sup> superionic behavior is associated with rotational motion of the thiophosphate polyanions pointing to a rotor phase, based on <i>ab initio</i> molecular dynamics simulations and supported by high‑temperature synchrotron and neutron diffraction, thermal analysis and impedance spectroscopy. These findings are of importance for the development of new polyanion‑based solid electrolytes.</p> </div>

On the Linear Geometry of Lanthanide Hydroxide (Ln—OH, Ln=La-Lu)

2019 ◽  
Author(s):  
Hassan Harb ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Triple Bond ◽  
Density Functional ◽  
Valence Electron ◽  
Density Functional Theory Calculations ◽  
Electron Configuration ◽  
Functional Theory ◽  
Key Species ◽  
Pi Orbitals ◽  
Lanthanide Hydroxide ◽  
Linear Geometry

Lanthanide hydroxides are key species in a variety of catalytic processes and in the preparation of corresponding oxides. This work explores the fundamental structure and bonding of the simplest lanthanide hydroxide, LnOH (Ln=La-Lu), using density functional theory calculations. Interestingly, the calculations predict that all structures of this series will be linear. Furthermore, these results indicate a valence electron configuration featuring an occupied sigma orbital and two occupied pi orbitals for all LnOH compounds, suggesting that the lanthanide-hydroxide bond is best characterized as a covalent triple bond.

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