scholarly journals Nanodiamond surface redox chemistry: influence of physicochemical properties on catalytic processes

2014 ◽  
Vol 172 ◽  
pp. 349-364 ◽  
Author(s):  
Thomas S. Varley ◽  
Meetal Hirani ◽  
George Harrison ◽  
Katherine B. Holt
Keyword(s):  
Electron Transfer ◽  
Proton Transfer ◽  
Physicochemical Properties ◽  
Redox Chemistry ◽  
Redox Species ◽  
Redox Active ◽  
Ph Dependent ◽  
Catalytic Processes ◽  
Surface Redox

Modification of an electrode with an immobilised layer of nanodiamond is found to significantly enhance the recorded currents for reversible oxidation of ferrocene methanol (FcMeOH). Current enhancement is related to nanodiamond diameter, with enhancement increasing in the order 1000 nm < 250 nm < 100 nm < 10 nm < 5 nm. We attribute the current enhancement to two catalytic processes: i) electron transfer between the solution redox species and redox-active groups on the nanodiamond surface; ii) electron transfer mediated by FcMeOH+ adsorbed onto the nanodiamond surface. The first process is pH dependent as it depends on nanodiamond surface functionalities for which electron transfer is coupled to proton transfer. The adsorption-mediated process is observed most readily at slow scan rates and is due to self-exchange between adsorbed FcMeOH+ and FcMeOH in solution. FcMeOH+ has a strong electrostatic affinity for the nanodiamond surface, as confirmed by in situ infrared (IR) experiments.

scholarly journals Quinone Redox-active Ionic Liquids

2017 ◽  
Vol 59 (4) ◽  
Author(s):  
Andrew Patrick Doherty ◽  
Sean Patterson ◽  
Laura Diaconu Diaconu ◽  
Louise Graham ◽  
Rachid Barhdadi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Solvent Free ◽  
Large Array ◽  
Transfer Processes ◽  
Redox Active ◽  
Electron Transfer Processes ◽  
Physical And Chemical

<p>Simple ionic liquids exhibit unique physical and chemical<br />properties that make them very useful for deployment in electrochemical<br />devices such as solvent-free electrolytes in capacitors and batteries.<br />However, incorporating redox functionality into ionic liquid<br />structures opens up in situ faradaic electrochemistry which allows access<br />to a large array of new electrochemical applications reliant upon<br />heterogeneous or homogenous electron-transfer processes. This paper<br />presents and discusses the opportunities and challenges for these types<br />of electro-materials across a myriad of applications by considering<br />exemplar quinone-functionalised ionic liquids.</p>

scholarly journals Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways

2020 ◽  
Vol 22 (44) ◽  
pp. 25467-25473 ◽  
Author(s):  
Keisuke Saito ◽  
Manoj Mandal ◽  
Hiroshi Ishikita
Keyword(s):  
Electron Transfer ◽  
Proton Transfer ◽  
Redox Potential ◽  
Driving Force ◽  
Electronic Coupling ◽  
Redox Potentials ◽  
Redox Active ◽  
Electron Transfer Pathways

Local proton transfer along redox-active low-barrier H-bonds can alter the driving force or electronic coupling for electron transfer, as the redox potential values depend on the H+ position in low-barrier H-bonds.

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.

Physicochemical properties of geopolymer composites with DFT calculations of in-situ reduction of graphene oxide

2021 ◽  
Author(s):  
Amun Amri ◽  
Ahmad Ainun Najib ◽  
Monita Olivia ◽  
Mohammednoor Altarawneh ◽  
Aman Syam ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dft Calculations ◽  
Physicochemical Properties ◽  
In Situ Reduction ◽  
Geopolymer Composites

scholarly journals Insight to Microbial Fe(III) Reduction Mediated by Redox-Active Humic Acids with Varied Redox Potentials

2021 ◽  
Vol 18 (13) ◽  
pp. 6807
Author(s):  
Jingtao Duan ◽  
Zhiyuan Xu ◽  
Zhen Yang ◽  
Jie Jiang
Keyword(s):  
Molecular Weight ◽  
Electron Transfer ◽  
Humic Acids ◽  
Weight Fraction ◽  
Electrochemical Analysis ◽  
Microbial Reduction ◽  
Redox Potentials ◽  
Groundwater Environment ◽  
Redox Active ◽  
Different Molecular Weight

Redox-active humic acids (HA) are ubiquitous in terrestrial and aquatic systems and are involved in numerous electron transfer reactions affecting biogeochemical processes and fates of pollutants in soil environments. Redox-active contaminants are trapped in soil micropores (<2 nm) that have limited access to microbes and HA. Therefore, the contaminants whose molecular structure and properties are not damaged accumulate in the soil micropores and become potential pollution sources. Electron transfer capacities (ETC) of HA reflecting redox activities of low molecular weight fraction (LMWF, <2.5) HA can be detected by an electrochemical method, which is related to redox potentials (Eh) in soil and aquatic environments. Nevertheless, electron accepting capacities (EAC) and electron donating capacities (EDC) of these LMWF HA at different Eh are still unknown. EDC and EAC of different molecular weight HA at different Eh were analyzed using electrochemical methods. EAC of LMWF at −0.59 V was 12 times higher than that at −0.49 V, while EAC increased to 2.6 times when the Eh decreased from −0.59 V to −0.69 V. Afterward, LMWF can act as a shuttle to stimulate microbial Fe(III) reduction processes in microbial reduction experiments. Additionally, EAC by electrochemical analysis at a range of −0.49–−0.59 V was comparable to total calculated ETC of different molecular weight fractions of HA by microbial reduction. Therefore, it is indicated that redox-active functional groups that can be reduced at Eh range of −0.49–−0.59 are available to microbial reduction. This finding contributes to a novel perspective in the protection and remediation of the groundwater environment in the biogeochemistry process.

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