Water Reduction with Visible Light: Synergy between Optical Transitions and Electron Transfer in Au-TiO2Catalysts Visualized by In situ EPR Spectroscopy

2013 ◽  
Vol 52 (43) ◽  
pp. 11420-11424 ◽  
Author(s):  
Jacqueline B. Priebe ◽  
Michael Karnahl ◽  
Henrik Junge ◽  
Matthias Beller ◽  
Dirk Hollmann ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Epr Spectroscopy ◽  
Optical Transitions ◽  
Water Reduction

Photoassisted Production of O2-• and H2 in Aqueous Medium Stimulated by Polythiophene in ZSM-5 Zeolite Channels

1999 ◽  
Vol 64 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Gabriel Čík ◽  
František Šeršeň ◽  
Alena Bumbálová
Keyword(s):  
Reactive Oxygen Species ◽  
Ion Exchange ◽  
Visible Light ◽  
Aqueous Medium ◽  
Exchange Reaction ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Water Reduction ◽  
Ion Exchange Reaction

The formation of reactive oxygen species due to irradiation by a visible light of the polythiophene deposited in ZSM-5 zeolite channels in aqueous medium has been studied. Polymerization of thiophene was carried out in zeolite channels after the ion-exchange reaction of Na+ for Fe3+. By means of EPR spectroscopy, the temporarily generated 1O2 in irradiated aqueous medium was proved. The formation of O2-• was confirmed by the reduction of Fe3+-cytochrome c. Irradiation led to the water reduction to hydrogen.

scholarly journals Donor-Acceptor Pyridinium Salts for Photo-Induced Electron Transfer Driven Modification of Tryptophan in Peptides, Proteins, and Proteomes using Visible Light

2021 ◽  
Author(s):  
Caleb Hoopes ◽  
Francisco Garcia ◽  
Akash Sarkar ◽  
Nicholas Kuehl ◽  
David Barkan ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Chemical Reactivity ◽  
Live Cells ◽  
Quantum Yields ◽  
Cell Labelling ◽  
Pyridinium Salts ◽  
Donor Acceptor ◽  
Photo Induced Electron Transfer

Tryptophan (Trp) plays a variety of critical functional roles in protein biochemistry however, owing to its low natural frequency and poor nucleophilicity, the design of effective methods for both single protein bioconjugation at Trp as well as for in situ chemoproteomic profiling re-mains a challenge. Here, we report a method for covalent Trp modification that is suitable for both scenarios by invoking photo-induced electron transfer (PET) as a means of driving efficient reactivity. We have engineered biaryl N-carbamoyl pyridinium salts that possess a donor-acceptor relationship enabling optical triggering with visible light whilst simultaneously attenuating the probe’s photo-oxidation potential in order to prevent photodegradation. This probe was assayed against a small bank of eight peptides and proteins, where it was found that micromolar concentrations of probe and short irradiation times (10-60 min) with violet light enabled efficient reactivity towards surface exposed Trp residues. The carbamate transferring group can be used to transfer useful functional groups to proteins including affinity tags and click handles. DFT calculations and other mechanistic analyses reveal correlations between excited state lifetimes, relative fluorescent quantum yields, and chemical reactivity. Biotinylated and azide-functionalized pyridinium salts were used for Trp profiling in HEK293T lysates and in situ in HEK293T cells using 450 nm LED irradiation. Peptide level enrichment from live cell labelling experiments identified 290 Trp modifications, with an 82% selectivity for Trp modification over other π-amino acids; demonstrating the ability of this method to identify and quantify reactive Trp residues from live cells.

In situ construction of MoS2@CoS2 spherical hydrangea-shaped clusters for enhanced visible-light photocatalytic degradation of sulfamethoxazole

2021 ◽  
Author(s):  
Liushu Pan ◽  
Chunlin Jiao ◽  
Yinna Liang ◽  
Jianhua Xiong ◽  
Shuangfei Wang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Noble Metals ◽  
Electron Traps ◽  
Co Catalysts ◽  
The Rich ◽  
Earth's Crust ◽  
Visible Light Photocatalytic

This article explores the rich element cobalt, found in the earth’s crust, to replace noble metals as co-catalysts that serve as electron traps to enhance the efficiency of electron transfer...

Tuning the Photocatalytic Performance of Plasmonic Nanocomposites (ZnO/Aux) Driven in Visible Light

2019 ◽  
Vol 8 (1) ◽  
pp. 56-61
Author(s):  
Aneeya K. Samantara ◽  
Debasrita Dash ◽  
Dipti L. Bhuyan ◽  
Namita Dalai ◽  
Bijayalaxmi Jena
Keyword(s):  
Electron Transfer ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Transfer Rate ◽  
Photocatalytic Performance ◽  
Light Exposure ◽  
Au Nanoparticle ◽  
Electron Transfer Rate ◽  
Au Nps ◽  
Zno Nanostructure

: In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites (NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases. The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity. Background: Due to the industrialization process, most of the toxic materials go into the water bodies, affecting the water and our ecological system. The conventional techniques to remove dyes are expensive and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been regarded as potential candidates for the removal of dye from the water system. Objective: To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface and the effect of the size of Au NPs for photocatalytic performance in the degradation process. Methods: A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed by a reduction of gold salt in the presence of ZnO nanostructure to form the composite. Results: ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer rate was discussed. Conclusion: Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.

In-situ synthesis of a hybrid Fe (Co)/MXene/ZSM-5 catalyst for phenol abatement

2021 ◽  
Author(s):  
Changquan Zhang ◽  
Chaolin Li ◽  
Gang Chen ◽  
Fei Ji ◽  
Yiyong Shen ◽  
...  
Keyword(s):  
Visible Light ◽  
Organic Pollutants ◽  
In Situ Synthesis ◽  
Sulfate Radical

Sulfate radical based photocatalysis is recognized as an effective approach for the photodegradation of organic pollutants in wastewater. To overcome the defects of weak visible light absorptivity and low catalytic...

The electron-transfer intermediates of the oxygen evolution reaction (OER) as polarons by in situ spectroscopy

2021 ◽  
Author(s):  
Hanna Lyle ◽  
Suryansh Singh ◽  
Michael Paolino ◽  
Ilya Vinogradov ◽  
Tanja Cuk
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Catalytic Reactions ◽  
In Situ Spectroscopy ◽  
Chemical Bonds

The conversion of diffusive forms of energy (electrical and light) into short, compact chemical bonds by catalytic reactions regularly involves moving a carrier from an environment that favors delocalization to one that favors localization.

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