scholarly journals Photocatalytic Water Oxidation Using Manganese Compounds Immobilized in Nafion Polymer Membranes

2011 ◽  
Vol 64 (9) ◽  
pp. 1221 ◽  
Author(s):  
Karin J. Young ◽  
Yunlong Gao ◽  
Gary W. Brudvig
Keyword(s):  
Tin Oxide ◽  
Water Oxidation ◽  
Polymer Membranes ◽  
Wavelength Dependence ◽  
Applied Potential ◽  
Solvent Water ◽  
Earth Abundant ◽  
Manganese Dioxide Nanoparticles ◽  
Glass Electrodes ◽  
Manganese Compounds

Robust water oxidation catalysts using earth abundant metals are required as part of an overall scheme to convert sunlight into fuels. Here, we report the immobilization of [Mn4IVO5(terpy)4(H2O)2](ClO4)6 (terpy = 2,2′;6′,2′′-terpyridine), [Mn4O6(tacn)4](ClO4)4 (tacn = 1,4,7-triazacyclononane), and manganese dioxide nanoparticles in Nafion on fluorine-doped tin oxide conducting glass electrodes. The electrodes are illuminated with white light in the presence of an applied potential and the resulting photocurrent is assigned to the oxidation of solvent water. Photodecomposition of the tetrameric complexes results in a material that is more active for light-driven electrooxidation of water. The reactivity, wavelength dependence, and stability of the compounds in Nafion under illumination are discussed.

Electrochemical Synthesis of Optically Active Polyanilines

1998 ◽  
Vol 51 (1) ◽  
pp. 23 ◽  
Author(s):  
Mir Reza Majidi ◽  
Leon A. P. Kane-Maguire ◽  
Gordon G. Wallace
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Quartz Crystal ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Spectroscopic Studies ◽  
Optically Active ◽  
Emeraldine Base ◽  
Applied Potential ◽  
Potential Cycling ◽  
Glass Electrodes

The synthesis of optically active polyaniline salt films of the type PAn.HCSA (HCSA = camphor-10-sulfonic acid) has been achieved via the enantioselective electropolymerization of aniline on indium-tin-oxide (ITO)-coated glass electrodes in the presence of (+)- or (–)-HCSA. Similar results were obtained under potentiostatic, galvanostatic and potentiodynamic conditions. The chiroptical and electrical properties of these novel materials have been characterized by u.v.–visible and circular dichroism (c.d.) spectroscopy, electrochemical quartz crystal microbalance techniques and resistometry. The intensity of the c.d. spectra of potentiostatically grown PAn.(+)-HCSA films was found to increase with increasing applied potential over the range 0·8–1·1 V (v. Ag/AgCl) and with increasing charge consumed. C.d. spectroscopic studies also showed that the polyaniline chains retained their initial configuration when the (+)-HCSA dopant acid in PAn.(+)-HCSA films was replaced by HCl via potential cycling in 1 mol dm-3 HCl. Similarly, chemical de-doping of PAn.(+)-HCSA with 0·5 mol dm-3 NH4OH produced optically active emeraldine base, which upon re-doping with HCl gave optically active PAn.HCl with a c.d. spectrum very similar to that of the original PAn.(+)-HCSA. These results suggest that chiral holes may be formed in the polymer matrix during both redox and chemical de-doping/re-doping cycles with PAn.(+)-HCSA salt films.

scholarly journals Fluorine‐Doped Tin Oxide/Alumina as Long‐Term Robust Conducting Support for Earth‐Abundant Water Oxidation Electrocatalysts

2019 ◽  
Vol 6 (8) ◽  
pp. 2282-2289 ◽  
Author(s):  
Felipe A. Garcés‐Pineda ◽  
Jesús González‐Cobos ◽  
Mabel Torrens ◽  
José R. Galán‐Mascarós
Keyword(s):  
Tin Oxide ◽  
Water Oxidation ◽  
Earth Abundant

scholarly journals Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review

2012 ◽  
Vol 9 (75) ◽  
pp. 2383-2395 ◽  
Author(s):  
Mohammad Mahdi Najafpour ◽  
Fahimeh Rahimi ◽  
Eva-Mari Aro ◽  
Choon-Hwan Lee ◽  
Suleyman I. Allakhverdiev
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Water Oxidation ◽  
Active Sites ◽  
Manganese Oxides ◽  
Metal Compounds ◽  
Functional Models ◽  
Current Densities ◽  
Conversion Efficiencies ◽  
Manganese Compounds

There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.

scholarly journals Correction: Enhanced photoelectrochemical water oxidation via atomic layer deposition of TiO2on fluorine-doped tin oxide nanoparticle films

Nanoscale ◽  
2015 ◽  
Vol 7 (28) ◽  
pp. 12226-12226 ◽  
Author(s):  
Isvar A. Cordova ◽  
Qing Peng ◽  
Isa L. Ferrall ◽  
Adam J. Rieth ◽  
Paul G. Hoertz ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Tin Oxide ◽  
Water Oxidation ◽  
Atomic Layer ◽  
Nanoparticle Films ◽  
Layer Deposition ◽  
Oxide Nanoparticle ◽  
Photoelectrochemical Water Oxidation

scholarly journals Aromaticity Driven Electrocatalytic Water Oxidation by a Phosphorus-Nitrogen PN3-Pincer Cobalt Complex

2019 ◽  
Author(s):  
Pradip K. Das ◽  
Sarmistha Bhunia ◽  
Priyanka Chakraborty ◽  
Atanu Rana ◽  
Abhishek Dey ◽  
...  
Keyword(s):  
Water Oxidation ◽  
High Efficiency ◽  
Cobalt Complex ◽  
Potential Jump ◽  
Onset Potential ◽  
New Strategy ◽  
Earth Abundant ◽  
High Valent ◽  
Lower Overpotential ◽  
Cobalt Species

Water oxidation is the primary step in both natural and artificial photosynthesis to convert solar energy in into chemical fuels. Herein, we report the first cobalt-based pincer catalyst for electrolytic water oxidation at neutral pH with high efficiency under electrochemical conditions. Most importantly, ligand (pseudo)aromaticity is identified to play an important role in the electrocatalysis. A significant potential jump (~300 mV) was achieved towards a lower positive value when the aromatized cobalt complex was transformed to a (pseudo)dearomatized cobalt species. This complex catalyzes the water oxidation in its high valent oxidation state at a much lower overpotential (~ 340 mV vs. NHE) based on the onset potential (0.5 mA/cm<sup>2</sup>) of catalysis at pH 10.5, outperforming all the other literature systems. These observations may provide a new strategy for the design of earth-abundant transition metal-based water oxidation catalysts.

Ultrathin alumina passivation for improved photoelectrochemical water oxidation catalysis of tin oxide sensitized by a phosphonate-functionalized perylene diimide first without, and then with, CoOy

2021 ◽  
Author(s):  
Carly F. Jewell ◽  
Ashwanth Subramanian ◽  
Chang-Yong Nam ◽  
Richard G. Finke
Keyword(s):  
Catalytic Activity ◽  
Tin Oxide ◽  
Water Oxidation ◽  
Oxidation Catalysis ◽  
Perylene Diimide ◽  
Water Oxidation Catalysis ◽  
Photoelectrochemical Water Oxidation

Deposition of an ultrathin AlOx overlayer applied by ALD on the PMPDI/SnO2 photoanode improves the photoactivity and catalytic activity of the system. ALD AlOx also helps support the understanding of the “anti-catalysis” behavior of added CoOy.

scholarly journals Photocatalytic water oxidation with a Prussian blue modified brown TiO2

2021 ◽  
Author(s):  
Gulsum Gundogdu ◽  
T. Gamze Ulusoy Ghobadi ◽  
Sina Sadigh Akbari ◽  
Ekmel Ozbay ◽  
Ferdi Karadas
Keyword(s):  
Prussian Blue ◽  
Water Oxidation ◽  
Prussian Blue Analogue ◽  
Earth Abundant

A CoFe Prussian blue analogue is coupled with brown TiO2 nanoparticles to achieve an earth-abundant photocatalytic water oxidation assembly.

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