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Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer. [ABSTRACT FROM AUTHOR]

We report reversible electrochemical capture and release of carbon dioxide using the well-known dye precursor and industrial catalyst anthraquinone. Although quinones are well-studied for electrochemical capture and release of CO2 in solution, we have discovered that a 100 nm film of anthraquinone can realize this in a heterogeneous fashion. In-depth spectroelectrochemical studies were performed in order to study the mechanism of this CO2 capture and release. Anthraquinone films reached an uptake capacity of 5.9 mmolCO2 gAQ−1. [ABSTRACT FROM AUTHOR]

In this report, we present results on the electrocatalytic activity of conducting polymers [polyaniline (PANI) and polypyrrole (PPy)] toward the electrochemical oxygen reduction reaction (ORR) to hydrogen peroxide (H 2 O 2 ). The electropolymerization of the polymers and electrolysis conditions were optimized for H 2 O 2 production. On flat glassy carbon (GC) electrodes, the faradaic efficiency (FE) for H 2 O 2 production was significantly improved by the polymers. Rotating disc electrode (RDE) studies revealed that this is mainly a result of blocking further H 2 O 2 to the water reduction pathway by the polymers. PPy on carbon paper (CP) significantly increased the molar production of H 2 O 2 by over 250% at an average FE of above 95% compared to bare CP with a FE of 25%. Thus, the polymers are acting as catalysts on the electrode for the ORR, although their catalytic mechanisms differ from other electrocatalysts., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

Two low molecular weight electroactive donor-acceptor-donor (DAD)-type molecules are reported, namely naphthalene bisimide (NBI) symmetrically core-functionalized with dithienopyrrole (NBI-(DTP) 2 ) and an asymmetric core-functionalized naphthalene bisimide with dithienopyrrole (DTP) substituent on one side and 2-ethylhexylamine on the other side (NBI-DTP-NHEtHex). Both compounds are characterized by low optical bandgaps (1.52 and 1.65 eV, respectively). NBI-(DTP) 2 undergoes oxidative electropolymerization giving the electroactive polymer of ambipolar character. Its two-step reversible reduction and oxidation is corroborated by complementary EPR and UV/Vis-NIR spectroelectrochemical investigations. The polymer turned out to be electrochemically active not only in aprotic solvents but also in aqueous electrolytes, showing a distinct photocathodic current attributed to proton reduction. Additionally, poly(NBI-(DTP) 2 ) was successfully tested as a photodiode material., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The current study reports the application of chalcopyrite semiconductor CuInS 2 (CIS) nanofibers for the reduction of CO 2 to CO with a remarkable Faradaic efficiency of 77 ± 4%. Initially the synthesis of CuInS 2 nanofibers was carried out by adaptable electrospinning technique. To reduce the imperfection in the crystalline fiber, polyacrylonitrile (PAN) was selected as template polymer. Afterward, the desired chemical structure of nanofibers was achieved through sulfurization process. Making continuous CuInS 2 nanofibers on the cathode surface by the electrospinning method brings the advantages of being economical, environmentally safe, and versatile. The obtained nanofibers of well investigated size and diameter according to the SEM (scanning electron microscope) were used in electrochemical studies. An improvement of Faradaic efficiency was achieved with the catalytic active CuInS 2 in nanofibrous structure as compared to the solution processed CuInS 2 . This underlines the important effect of the electrode fabrication on the catalytic performance. Being less contaminated as compared to solution processing, and having a well-defined composition and increased catalytically active area, the CuInS 2 nanofiber electrodes prepared by the electrospinning technique show a 4 times higher Faradaic efficiency. Furthermore, in this study, attention was paid to the stability of the CuInS 2 nanofiber electrodes. The electrochemical reduction of CO 2 to CO by using CIS nanofibers coated onto FTO electrodes was carried out for 10 h in total. The observed current density of 0.22 mA cm -2 and the stability of CIS nanofiber electrodes are found to be competitive with other heterogeneous electrocatalysts. Hence, we believe that the fabrication and application of nanofibrous materials through the electrospinning technique might be of interest for electrocatalytic studies in CO 2 reduction.

Limiting anthropogenic carbon dioxide emissions constitutes a major issue faced by scientists today. Herein we report an efficient way of controlled capture and release of carbon dioxide using nature inspired, cheap, abundant and non-toxic, industrial pigment namely, quinacridone. An electrochemically reduced electrode consisting of a quinacridone thin film (ca. 100 nm thick) on an ITO support forms a quinacridone carbonate salt. The captured CO2 can be released by electrochemical oxidation. The amount of captured CO2 was quantified by FT-IR. The uptake value for electrochemical release process was 4.61 mmol g(-1). This value is among the highest reported uptake efficiencies for electrochemical CO2 capture. For comparison, the state-of-the-art aqueous amine industrial capture process has an uptake efficiency of ca. 8 mmol g(-1)., (© 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.)