scholarly journals Efficient Electrochemical Reduction of CO2 to Formate in Methanol Solutions by Mn Functionalized Electrodes in the Presence of Amines

2021 ◽  
Author(s):  
Francesca Marocco Studardi ◽  
Arianna Tiozzo ◽  
Laura Rotundo ◽  
Roberto Gobetto ◽  
Carlo Nervi ◽  
...  
Keyword(s):  
Liquid Fuel ◽  
Reduced Form ◽  
Carbon Cloth ◽  
Co Catalyst ◽  
Methanol Solutions ◽  
Covalently Bonded ◽  
Electrochemical Mechanism ◽  
Reduction Of Co2 ◽  
Organometallic Catalyst ◽  
Shed Light

Carbon cloth electrode modified by covalently attaching a manganese organometallic catalyst is used as cathode for the electrochemical recuction of CO2 in methanol solutions. Six different amines are employed as co-catalyst in millimolar concentrations, which coupled to the increased solubility of CO2 in methanol enhance the formate production, switch the selectivity toward formate anion, and in the case of pentamethyldiethylentriamine (PMDETA) resulted in an impressive TONHCOO– of 2.8×104. We demonstrate that the protonated PMDETA is formed in methanol solution by simply bubbling CO2, which is the responsible for a barrierless transformation of CO2 to formate via the reduced form of the Mn catalyst covalently bonded to the electrode surface. These findings pave the way for more efficient transformation of CO2 into liquid fuel and shed light on the electrochemical mechanism

scholarly journals Photocatalytic reduction of CO2 over exposed-crystal-face-controlled TiO2 nanorod having a brookite phase with co-catalyst loading

2014 ◽  
Vol 152-153 ◽  
pp. 309-316 ◽  
Author(s):  
Teruhisa Ohno ◽  
Takayoshi Higo ◽  
Naoya Murakami ◽  
Hirofumi Saito ◽  
Qitao Zhang ◽  
...  
Keyword(s):  
Photocatalytic Reduction ◽  
Catalyst Loading ◽  
Crystal Face ◽  
Co Catalyst ◽  
Tio2 Nanorod ◽  
Reduction Of Co2 ◽  
Brookite Phase

scholarly journals Arsenic Detoxification by Geobacter Species

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Yan Dang ◽  
David J. F. Walker ◽  
Kaitlin E. Vautour ◽  
Steven Dixon ◽  
Dawn E. Holmes
Keyword(s):  
Efflux Pump ◽  
Reduced Form ◽  
Content Type ◽  
Sedimentary Environments ◽  
Arsenic Mobility ◽  
Subsurface Environments ◽  
Detoxification System ◽  
Arsenic Detoxification ◽  
Arsenic Transformation ◽  
Shed Light

ABSTRACT Insight into the mechanisms for arsenic detoxification by Geobacter species is expected to improve the understanding of global cycling of arsenic in iron-rich subsurface sedimentary environments. Analysis of 14 different Geobacter genomes showed that all of these species have genes coding for an arsenic detoxification system (ars operon), and several have genes required for arsenic respiration (arr operon) and methylation (arsM). Genes encoding four arsenic repressor-like proteins were detected in the genome of G. sulfurreducens; however, only one (ArsR1) regulated transcription of the ars operon. Elimination of arsR1 from the G. sulfurreducens chromosome resulted in enhanced transcription of genes coding for the arsenic efflux pump (Acr3) and arsenate reductase (ArsC). When the gene coding for Acr3 was deleted, cells were not able to grow in the presence of either the oxidized or reduced form of arsenic, while arsC deletion mutants could grow in the presence of arsenite but not arsenate. These studies shed light on how Geobacter influences arsenic mobility in anoxic sediments and may help us develop methods to remediate arsenic contamination in the subsurface. IMPORTANCE This study examines arsenic transformation mechanisms utilized by Geobacter, a genus of iron-reducing bacteria that are predominant in many anoxic iron-rich subsurface environments. Geobacter species play a major role in microbially mediated arsenic release from metal hydroxides in the subsurface. This release raises arsenic concentrations in drinking water to levels that are high enough to cause major health problems. Therefore, information obtained from studies of Geobacter should shed light on arsenic cycling in iron-rich subsurface sedimentary environments, which may help reduce arsenic-associated illnesses. These studies should also help in the development of biosensors that can be used to detect arsenic contaminants in anoxic subsurface environments. We examined 14 different Geobacter genomes and found that all of these species possess genes coding for an arsenic detoxification system (ars operon), and some also have genes required for arsenic respiration (arr operon) and arsenic methylation (arsM).

scholarly journals Selective hydrogenation of nitroarenes using an electrogenerated polyoxometalate redox mediator

2018 ◽  
Vol 54 (9) ◽  
pp. 1093-1096 ◽  
Author(s):  
Lewis MacDonald ◽  
Benjamin Rausch ◽  
Mark D. Symes ◽  
Leroy Cronin
Keyword(s):  
Selective Hydrogenation ◽  
Redox Mediator ◽  
Reduced Form ◽  
Silicotungstic Acid ◽  
Co Catalyst

The 2-electron reduced form of the polyoxometalate silicotungstic acid (H4[SiW12O4]) is shown to be an effective and selective hydrogenation agent for a range of nitroarenes without the need for any co-catalyst.

scholarly journals Quantitative Electro-Reduction of CO2 to Liquid Fuel over Electro-Synthesized Metal–Organic Frameworks

2020 ◽  
Vol 142 (41) ◽  
pp. 17384-17392
Author(s):  
Xinchen Kang ◽  
Bin Wang ◽  
Kui Hu ◽  
Kai Lyu ◽  
Xue Han ◽  
...  
Keyword(s):  
Liquid Fuel ◽  
Metal Organic Frameworks ◽  
Metal Organic ◽  
Reduction Of Co2

Modeling the Dynamics of the Hong Kong Office Market under Economic Structural Change

10.1068/b3198 ◽  
2005 ◽  
Vol 32 (1) ◽  
pp. 111-125 ◽  
Author(s):  
Winky K O Ho
Keyword(s):  
Hong Kong ◽  
Structural Change ◽  
Reduced Form ◽  
Adjustment Mechanism ◽  
Office Space ◽  
Office Market ◽  
Office Employment ◽  
Office Rent ◽  
The One ◽  
Shed Light

The author adopts reduced-form equilibrium models to investigate the relations among vacancy, employment, space consumption, and rent in the Hong Kong office market under economic structural change. The models are estimated with the aid of data from Hong Kong during the period 1980–2002—a total of twenty-three yearly observations. It is hoped that empirical results will shed light on the adjustment mechanism of the local office market. In line with the existing literature, the author shows that, on the one hand, office rent is positively related to office employment, but inversely related to office stock. On the other hand, the demand for office space is inversely related to rent, but positively related to office employment. Moreover, the elasticity of space consumption with respect to rent is estimated to be inelastic. Historical simulations of the model are performed, and it is suggested that the equations simulate reasonably well as indicated by Theil's inequality.

scholarly journals Type 2-depleted fungal laccase

1988 ◽  
Vol 253 (2) ◽  
pp. 561-568 ◽  
Author(s):  
P M Hanna ◽  
D R McMillin ◽  
M Pasenkiewicz-Gierula ◽  
W E Antholine ◽  
B Reinhammar
Keyword(s):  
Molar Absorptivity ◽  
Reduced Form ◽  
Intramolecular Electron Transfer ◽  
Visible Absorption ◽  
Fungal Laccase ◽  
Covalently Bonded ◽  
High Concentrations ◽  
Type 3

Although copper is quantitatively removed from fungal laccase (Polyporus versicolor) by extended dialysis against high concentrations of cyanide, we have been unable to reconstitute the protein by addition of Cu(I) ions. However, two new methods for reversibly removing the type 2 Cu centre have been developed. The visible absorption at 610 nm, which is attributable to type 1 Cu, is unaffected by the procedure, but the absorbance of the type 3 Cu at 330 nm is decreased by 60 +/- 10%. The decrease is due, at least in part, to partial reduction of the binuclear type 3 centre, although there may be some change in the molar absorptivity of the oxidized chromophore as well. The change in the c.d. spectrum that occurs at approx. 350 nm may be explained in the same way, but it may also reflect the loss of a signal due to the type 2 Cu. Upon removal of the type 2 Cu an absorbance increase appears at approx. 435 nm, and it is assigned to the semi-reduced form of the type 3 pair. In the e.p.r. spectrum of the type 2-depleted enzyme the type 1 Cu signal exhibits well-resolved ligand hyperfine splitting, which can be simulated on the basis of contributions from two N and two H nuclei (AH congruent to AN congruent to 25 MHz). The H atoms are assumed to be attached to the beta-carbon of the covalently bonded cysteine ligand. A signal from a semi-reduced form(s) of the type 3 site can also be resolved in the spectrum of the type 2-depleted enzyme, and on the basis of the second integral of the e.p.r. spectrum 40% of the type 3 pairs are believed to be in a partially reduced state. The semi-reduced type 3 site is remarkably stable and is not readily oxidized by H2O2 or IrCl6(2-) or reduced by Fe(CN)6(4-). Intramolecular electron transfer is apparently quite slow in at least some forms of the type 2-depleted enzyme, and this may explain why the activity is at best 5% of that of the native enzyme. Full activity returns when type 2 copper is restored.

EXPRESS: Comparing individual and collective management of referential choices in dialogue

2021 ◽  
pp. 174702182110371
Author(s):  
Dominique Knutsen ◽  
Marion Fossard ◽  
Amélie M. Achim
Keyword(s):  
Past Research ◽  
Reduced Form ◽  
Discourse Referent ◽  
Collective Management ◽  
Conversational Partner ◽  
Signal Understanding ◽  
Reduced Forms ◽  
Shed Light

Past research shows that when a discourse referent is mentioned repeatedly, it is usually introduced with a full NP and maintained with a reduced form such as a pronoun. Is this also the case in dialogue, where the same referent may be introduced by one person and maintained by another person? An experiment was conducted in which participants either told entire stories to each other or told stories together, thus enabling us to contrast situations in which characters were introduced and maintained by the same person (control condition) and situations in which the introduction and the maintaining of each character were performed by different people (alternating condition). Story complexity was also manipulated through the introduction of one or two characters in each story. We found that participants were less likely to use reduced forms to maintain referents in the alternating condition. The use of reduced forms also depended on the context in which the referent was maintained (in particular, first or second mention of a character) and on story complexity. These results shed light on how the pressure to signal understanding to one’s conversational partner affects referential choices throughout the interaction.

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