Reduction Of Molecular Nitrogen Research Articles

Recent progress in research and design concepts for the characterization, testing, and photocatalysts for nitrogen reduction reaction

AbstractThe reduction of molecular nitrogen (N2) to ammonia (NH3) under mild conditions is one of the most promising studies in the energy field due to the important role of NH3 in modern industry, production, and life. The photocatalytic reduction of N2 is expected to achieve clean and sustainable NH3 production by using clean solar energy. To date, the new photocatalysts for photocatalytic reduction of N2 to NH3 at room temperature and atmospheric pressure have not been fully developed. The major challenge is to achieve high light‐absorption efficiency, conversion efficiency, and stability of photocatalysts. Herein, the methods for measuring produced NH3 are compared, and the problems related to possible NH3 pollution in photocatalytic systems are mentioned to provide accurate ideas for measuring photocatalytic efficiency. The recent progress of nitrogen reduction reaction (NRR) photocatalysts at ambient temperature and pressure is summarized by introducing charge transfer, migration, and separation in photocatalytic NRR, which provides guidance for the selection of future photocatalyst selection. More importantly, we introduce the latest research strategies of photocatalysts in detail, which can guide the preparation and design of photocatalysts with high NRR activity.

Catalytic behavior of a polynuclear Mg-Mo complex and nitrogenase active site (FeMoco) isolated from the enzyme in reactions with C2H2, N2, and CO: A comparative study

In order to identify common and distinctive features in the catalytic behavior of natural and artificial nitrogen-fixation clusters, the kinetics of the catalytic reduction of C2H2 in the presence of Mg-Mo-cluster (1) was investigated and compared with the kinetics of acetylene reduction catalyzed by the cluster FeMoco (2) isolated from the enzyme nitrogenase we studied previously. The reactions were conducted in the presence of Zn/Hg and Eu/Hg as reducing agents and PhSH and C6F5SH as proton donors, i.e., under the same conditions as had been used in the case of 2. Both polynuclear Mg-Mo-complex and the europium amalgam-reduced FeMoco have multiple interdependent binding sites for substrates and/or inhibitors. Carbon monoxide inhibits the acetylene reduction much less efficiently in systems with cluster 1 than in systems with cluster 2, although the type of inhibition is mixed in both systems: CO binds to multiple sites of the cluster and affects both C2H2 complexation to the reduced cluster and decomposition of the catalyst-substrate complex to give the products. Unlike isolated FeMoco, the Mg-Mo-cluster efficiently catalyzes the reduction of molecular nitrogen. The reaction is greatly inhibited by acetylene, while no inhibiting effect of N2 is observed in acetylene reduction, as was found earlier for a system with the natural cluster as the catalyst.

Thermodynamics of the mechanism of the nitrogenase reaction

The fixation of molecular nitrogen by nitrogenase requires a lot of energy because 16 mol of ATP are hydrolyzed per mole of nitrogen converted to ammonia. Kim and Dees determined the crystallograpic structure of nitrogenase and this has led to a three-step mechanism that involves Feprotein and MoFeprotein in addition to ferredoxin. Each of these steps can be interpreted in terms of two half reactions that are connected through their transfer of electrons. Estimates can be made of the standard apparent reduction potentials of these three steps and their dependencies on pH and ionic strength. This mechanism is compared with the same type of analysis of an alternative three-step mechanism in which the hydrolysis of ATP is coupled with the reduction of molecular nitrogen, rather than the reduction of Feprotein. The problem with the first mechanism is that the second step produces 12 mol of hydrogen ions per mole of nitrogen fixed and the third step consumes 10 mol of hydrogen ions per mole of nitrogen fixed. The alternative mechanism does not have this problem.

Mechanism of the reduction of molecular nitrogen to hydrazine by niobium (iii) hydroxide

The effect of the concentration of water on the rate of reduction of molecular nitrogen to hydrazine by niobium(iii) hydroxide in alkaline H2O−MeOH and D2O−MeOD mixtures was studied. In both cases, the reaction rate is maximum when [H2O]=4 mol L−1, and the inverse isotopic effect (KD/kH>1) is observed when [H2O]<20 mol L−1. Similar regularity was observed for the reaction of hydrogen elimination. It was found that HD is formed in the H2O−MeOH system in the presence of D2. The conclusion was made that the ratedetermining stage in hydrazine formation is the transfer of a hydride ion to the dinitrogen molecule coordinated to the binuclear NbIII center. A kinetic scheme satisfactorily explaining the effect of the concentration of water ([H2O]=1.5−49.0 mol L−1) on the reaction rate constant was proposed.

Two-path reduction of molecular nitrogen by transition metal hydroxides

The kinetics of the reduction of N2 to N2H4 and NH3 by TiIII-MoIII hydroxide was studied at pH I I and 303-333 K, and the activation energies for these reactions and also for the reaction N2H4 → 2 NH3 were determined (29, 70, and 25 kJ mol− respectively). It was concluded that -90 % of ammonia was formed by the direct reduction of N2 without intermediate formation of hydrazine. A mechanism of this reaction is suggested, which includes the proton insertion into the N-N bond favored by an enhanced electron density at the nitrogen atoms, according to the data of the quantum-mechanical calculation.

Fixation and reduction of molecular nitrogen by [WH4(PC2H5Ph2)4] and [WH4(PCH3Ph2)4] in a γ-radiation field

Hydride complexes of W(IV) with dpep (diphenylethylphosphine) and dpmp (diphenylmethylphosphine) were irradiated in thf+C6H12(1∶1) solutions, saturated with N2+H2(1∶3). Radiation yields of hydrazine, ammonia and amines were evaluated. The mechanism of reduction of molecular nitrogen is discussed.

Radiation induced conversion of N 2 to amines in the presence of [WH 4(dppe) 2] and [WH 5(dppe) 2] + in solution

The complexes [WH 4(dppe) 2] and [WH 5(dppe) 2][HSO 4] were applied in the fixation and reduction of molecular nitrogen in a γ-radiation field. The mechanism of the process involving the reactions with the solvent molecules was presented. Dependences of the yields of the amines formed on the dose and concentrations of the catalyst were shown.

Radiation-catalytic reduction of molecular nitrogen with application of the tungsten(IV) hydride complexes

A radiation-catalytic experiment of the fixation and reduction of molecular nitrogen has been carried out. The [WH 4(dtpe) 2] complex was applied to fix molecular nitrogen in a γ-radiation field. Plots of the dependence of either the number of molecules of ammonia or hydrazine vs dose are presented. A mechanism for the radiation-catalytic fixation and reduction of molecular nitrogen using the [WH 4(dtpe) 2] complex is suggested. The unusually high radiation yields of ammonia and hydrazine are explained as due to a cyclic process.

The cyclic fixation and reduction of molecular nitrogen with [WH4(Ph2PCH2CH2PPh2)2] in γ-irradiated solutions

Yields of NH3 and N2H4 in radiation-catalytic reduction of N2 by means of a hydride complex of WIV with dppe in thf solution and in mixtures of thf with other solvents have been estimated. A mechanism proposed earlier of reduction of coordinated N2 has been confirmed and the role of solvent in reduction of N2 to NH3 and amines has been explained.

Radiation-catalytic reduction of the −NNH2 group in [Mo(NNH2)(HSO4)(DPPE)2]HSO4 in methanol solution

The molybdenum hydrazido complex [Mo(NHH2)(HSO4)(dppe)2]HSO4 was used in the process of fixation and reduction of molecular nitrogen in γ-radiation field. This process has been found as a catalytic one. Results of this work generally confirm conclusions of the previous works and some new aspects of the mechanism of this process are discussed.

Yields of NH3 in radiation-catalytic reduction of molecular nitrogen

The [MoOC1(dppe)2]Cl complex [dppe=(C6H6)2P(CH2)2 P(C6H5)2] was successfully examined in a process of reduction of molecular nitrogen in γ-radiation field. Yields of ammonia produced in this process were measured as a function of the Mo(IV) complex concentration and dose.

Polarographic study of Mo(V) in methanol in the presence of phosphatidyl choline

1. Adsorption of phosphatidyl choline on a mercury drop electrode and its effect on reduction of Mo(V) in methanol alkaline and guanidine buffer solutions were studied by the methods of classic and alternating current polarography and it was shown that Mo(V) forms a complex with the polar part of the phosphatidyl choline molecule. 2. It was hypothesized that the complex of molybdenum with the phospholipid increases the yield of hydrazine in the reaction of reduction of molecular nitrogen.

ChemInform Abstract: Hydrogen Evolving Systems. Part 6. Reduction of Molecular Nitrogen in Molybdenum(III‐V) Hydroxide/Titanium(III) Hydroxide Systems.

AbstractDie stöchiometrische Reduktion von N2 zu N2H4 mit Hilfe des durch gemeinsame Fällung hergestellten Systems Mo(III‐V)‐hydroxid/Ti(III)‐hydroxid bei 20°C in 95proz. wäßrigem MeOH erfolgt an aktiven Mo(IV)‐Plätzen, und zwar am besten bei Mo/Ti‐Verhältnissen zwischen 0.1 und 0.2.

Hydrogen evolving systems. 6. Reduction of molecular nitrogen in molybdenum(III-V) hydroxide/titanium(III) hydroxide systems

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen evolving systems. 6. Reduction of molecular nitrogen in molybdenum(III-V) hydroxide/titanium(III) hydroxide systemsNan Hui Liu, Norman Strampach, and Gerhard N. SchrauzerCite this: Inorg. Chem. 1984, 23, 18, 2772–2777Publication Date (Print):August 1, 1984Publication History Published online1 May 2002Published inissue 1 August 1984https://doi.org/10.1021/ic00186a012RIGHTS & PERMISSIONSArticle Views108Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (690 KB) Get e-Alerts Get e-Alerts

Hydrogen-evolving systems. 4. The reduction of molecular nitrogen and of other substrates in the vanadium(II)-pyrocatechol system

Hydrogen-evolving systems. 4. The reduction of molecular nitrogen and of other substrates in the vanadium(II)-pyrocatechol system

Electrocatalytic properties of the Ti(OH)3−Mo(III) system in the reduction of molecular nitrogen

Electrochemical reduction studies of dinitrogen catalyzed by Ti(OH)3−Mo(III) in an alkaline methanol solution on a mercury cathode show that the maximum yield of hydrazine (4%) and ammonia (43%) is observed at 0.5 mA/cm2 current density. In experimental conditions it corresponds to the zero-charge potential of sodium amalgam (−1.86 V).

Fixation and reduction of molecular nitrogen during irradiation of phosphine hydride complexes of tungsten and molybdenum

A new photochemical reaction was discovered for the fixation and reduction of molecular nitrogen by the irradiation of the phosphine hydride complexes H4ML4, where M=W or Mo, and L=triphenylphosphine derivatives, in an N2 atmosphere in organic solvents as the medium.

Chemical evolution of a nitrogenase model. 18. Reduction of molecular nitrogen with molybdoinsulin catalysts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical evolution of a nitrogenase model. 18. Reduction of molecular nitrogen with molybdoinsulin catalystsBarbara J. Weathers, John H. Grate, Norman A. Strampach, and Gerhard N. SchrauzerCite this: J. Am. Chem. Soc. 1979, 101, 4, 925–928Publication Date (Print):February 1, 1979Publication History Published online1 May 2002Published inissue 1 February 1979https://doi.org/10.1021/ja00498a021RIGHTS & PERMISSIONSArticle Views82Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (508 KB) Get e-Alerts Get e-Alerts

Hydrogen evolving systems. 3. Further observations on the reduction of molecular nitrogen and of other substrates in the vanadium(II) hydroxide-magnesium hydroxide system

Hydrogen evolving systems. 3. Further observations on the reduction of molecular nitrogen and of other substrates in the vanadium(II) hydroxide-magnesium hydroxide system

Additions and Corrections - The Reduction of Molecular Nitrogen, Organic Substrates and Protons by Vanadium(II)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdditions and Corrections - The Reduction of Molecular Nitrogen, Organic Substrates and Protons by Vanadium(II)S. Zones, T. Vickrey, J. Palmer, and G. SchrauzerCite this: J. Am. Chem. Soc. 1977, 99, 15, 5228Publication Date (Print):June 1, 1977Publication History Published online11 February 2004Published inissue 1 June 1977https://doi.org/10.1021/ja00457a601RIGHTS & PERMISSIONSArticle Views24Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (125 KB) Get e-Alerts Get e-Alerts