scholarly journals Identification of Photoexcited Electron Relaxation in a Cobalt Phosphide Modified Carbon Nitride Photocatalyst

ChemPhotoChem ◽  
2021 ◽  
Author(s):  
Guang X. Pei ◽  
Nelson Y. Dzade ◽  
Yue Zhang ◽  
Jan P. Hofmann ◽  
Nora H. Leeuw ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Photoexcited Electron ◽  
Cobalt Phosphide ◽  
Electron Relaxation

Noble-metal-free cobalt phosphide modified carbon nitride: An efficient photocatalyst for hydrogen generation

2017 ◽  
Vol 200 ◽  
pp. 477-483 ◽  
Author(s):  
Sha-Sha Yi ◽  
Jun-Min Yan ◽  
Ba-Ri Wulan ◽  
Si-Jia Li ◽  
Kai-Hua Liu ◽  
...  
Keyword(s):  
Noble Metal ◽  
Carbon Nitride ◽  
Hydrogen Generation ◽  
Metal Free ◽  
Cobalt Phosphide

scholarly journals Effective Photocatalytic Hydrogen Evolution Using Covalent Triazine Framework-Derived Carbon Nitride Nanofiber Containing Carbon Vacancies for Visible-Light-Driven

2021 ◽  
Vol 11 (16) ◽  
pp. 7222
Author(s):  
Liangjing Zhang ◽  
Aiwu Wang ◽  
Mei Zhang ◽  
Zhengyuan Jin ◽  
Huan Yi ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Active Sites ◽  
Carbon Nitride ◽  
Light Irradiation ◽  
H2 Evolution ◽  
Photoexcited Electron ◽  
Energy And Environment ◽  
Visible Light Driven ◽  
Covalent Triazine Framework

In this study, a novel fibrous carbon nitride (FCN) was prepared from laminated covalent triazine framework (CTF) via pyrolysis, using functionalized 2,5-thiophenedicarboxylic acid and melamine as the precursors. A carbon vacancy was produced by two-step calcination in argon and air atmospheres. These carbon vacancies further exposed the edges and diffusion channels of the FCN nanofibers, which accelerated photogenerated charge transfer and provided more active sites. The FCN was characterized using various techniques and used for H2 evolution under visible-light irradiation. The as-synthesized FCN exhibited excellent stability, and its photocatalytic activity for H2 evolution under visible-light irradiation was 66 times higher than that of bare C3N4 (BCN), attaining a maximum H2 evolution rate of 102.63 μmol in 6 h. The FCN remained stable following visible-light irradiation at the end of 10 cycles. The FCN benefited from the absorption of solar energy and a large number of active sites. These advantages facilitated the efficient separation of photoexcited electron-hole pairs to hinder charge recombination. This work generates new insights into the preparation of highly effective FCN photocatalysts that may be put to various applications, especially in the fields of energy and environment.

Bimetallic Manganese Cobalt Phosphide Nanodots–Modified Graphitic Carbon Nitride for High‐Performance Hydrogen Production

2019 ◽  
Vol 7 (5) ◽  
pp. 1800927 ◽  
Author(s):  
Jiacong Wu ◽  
Chunmei Li ◽  
Wenli Zhang ◽  
Juan Han ◽  
Lei Wang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
High Performance ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Cobalt Phosphide

Photoexcited electron relaxation processes in single-wall carbon nanotubes

2005 ◽  
Vol 71 (4) ◽  
Author(s):  
J. Jiang ◽  
R. Saito ◽  
A. Grüneis ◽  
S. G. Chou ◽  
Ge. G. Samsonidze ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Single Wall Carbon Nanotubes ◽  
Relaxation Processes ◽  
Photoexcited Electron ◽  
Single Wall Carbon ◽  
Electron Relaxation

scholarly journals Parametric dependence of hot electron relaxation timescales on electron-electron and electron-phonon interaction strengths

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Richard B. Wilson ◽  
Sinisa Coh
Keyword(s):  
Relaxation Times ◽  
High Energy ◽  
Hot Electron ◽  
Electronic Subsystem ◽  
Electron Dynamics ◽  
Phonon Interaction ◽  
Photoexcited Electron ◽  
Electron Phonon Interaction ◽  
Electron Relaxation ◽  
Scattering Rates

AbstractUnderstanding how photoexcited electron dynamics depend on electron-electron (e-e) and electron-phonon (e-p) interaction strengths is important for many fields, e.g. ultrafast magnetism, photocatalysis, plasmonics, and others. Here, we report simple expressions that capture the interplay of e-e and e-p interactions on electron distribution relaxation times. We observe a dependence of the dynamics on e-e and e-p interaction strengths that is universal to most metals and is also counterintuitive. While only e-p interactions reduce the total energy stored by excited electrons, the time for energy to leave the electronic subsystem also depends on e-e interaction strengths because e-e interactions increase the number of electrons emitting phonons. The effect of e-e interactions on energy-relaxation is largest in metals with strong e-p interactions. Finally, the time high energy electron states remain occupied depends only on the strength of e-e interactions, even if e-p scattering rates are much greater than e-e scattering rates.

Preparation and characterization of thin films of carbon nitride

1995 ◽  
Vol 53 ◽  
pp. 104-105
Author(s):  
L. Wan ◽  
R. F. Egerton
Keyword(s):  
Carbon Nitride ◽  
Arc Discharge ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Reactive Sputtering ◽  
Vacuum Arc ◽  
Specimen Preparation ◽  
Bonding Structure ◽  
Electron Energy Loss

INTRODUCTION Recently, a new compound carbon nitride (CNx) has captured the attention of materials scientists, resulting from the prediction of a metastable crystal structure β-C3N4. Calculations showed that the mechanical properties of β-C3N4 are close to those of diamond. Various methods, including high pressure synthesis, ion beam deposition, chemical vapor deposition, plasma enhanced evaporation, and reactive sputtering, have been used in an attempt to make this compound. In this paper, we present the results of electron energy loss spectroscopy (EELS) analysis of composition and bonding structure of CNX films deposited by two different methods.SPECIMEN PREPARATION Specimens were prepared by arc-discharge evaporation and reactive sputtering. The apparatus for evaporation is similar to the traditional setup of vacuum arc-discharge evaporation, but working in a 0.05 torr ambient of nitrogen or ammonia. A bias was applied between the carbon source and the substrate in order to generate more ions and electrons and change their energy. During deposition, this bias causes a secondary discharge between the source and the substrate.

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

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