Natural and Engineered Electron Transfer of Nitrogenase

Gu, Wenyu; Milton, Ross D.

doi:10.3390/chemistry2020021

Cited by 21 publications

(11 citation statements)

References 171 publications

(229 reference statements)

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“…In the last several decades, the theoretical and experimental foundations of these processes were developed, improving our understanding thereof. Establishing electrical communication between redox proteins and electrodes or inorganic nanomaterials is a major challenge that has been at the forefront of research for the last two decades [7,8]. Using redox mediators or directed electron transfer configurations has led to a variety of sensing or energy generating devices.…”

Section: Introductionmentioning

confidence: 99%

Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes

2020

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Nitrogenase, a bacteria-based enzyme, is the sole enzyme that is able to generate ammonia by atmospheric nitrogen fixation. Thus, improved understanding of its utilization and developing methods to artificially activate it may contribute to basic research, as well as to the design of future artificial systems. Here, we present methods to artificially activate nitrogenase using photoinduced reactions. Two nitrogenase variants originating from Azotobacter vinelandii were examined using photoactivated CdS nanoparticles (NPs) capped with thioglycolic acid (TGA) or 2-mercaptoethanol (ME) ligands. The effect of methyl viologen (MV) as a redox mediator of hydrogen and ammonia generation was tested and analyzed. We further determined the NPs conductive band edges and their effect on the nitrogenase photoactivation. The nano-biohybrid systems comprising CdS NPs and nitrogenase were further imaged by transmission electron microscopy, visualizing their formation for the first time. Our results show that the ME-capped CdS NPs–nitrogenase enzyme biohybrid system with added MV as a redox mediator leads to a five-fold increase in the production of ammonia compared with the non-mediated biohybrid system; nevertheless, it stills lag behind the natural process rate. On the contrary, a maximal hydrogen generation amount was achieved by the αL158C MoFe-P and the ME-capped CdS NPs.

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Section: Introductionmentioning

confidence: 99%

Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes

2020

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“…In comparison, the well-known nitrogenase enzyme, which reduces N2 to NH3, was measured electrochemically to have an electron transfer TOF of 1.2×10 4 hr -1 . 44 Similarly, we can compare to photocatalytic systems. In an iridium photocatalytic system tuned for CO2 reduction, the highest observed TOF was 22 hr -1 .…”

Section: Results and Discussion Of Photoinduced Charge Transfer To Co...mentioning

confidence: 99%

Photoinduced Charge Transfer from Quantum Dots Measured by Cyclic Voltammetry

et al. 2022

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Measuring and modulating charge-transfer processes at quantum dot interfaces are crucial steps in developing quantum dots as photocatalysts. In this work, cyclic voltammetry under illumination is demonstrated to measure the rate of photoinduced charge transfer from CdS quantum dots by directly probing the changing oxidation states of a library of molecular charge acceptors. The voltammetry data demonstrates the presence of long-lived electron donor states generated by native photodoping of the quantum dots as well as a positive correlation between driving force and rate of charge transfer. Changes to the voltammograms under illumination follow mechanistic predictions from classic zone diagrams and electrochemical modeling allows for measurement of the rate of productive electron transfer. Rate constants for photoinduced charge transfer on the order of 10 4 M -1 s -1 are calculated, which are distinct from the picosecond dynamics measured by conventional transient optical spectroscopy methods and are more closely connected to the quantum yield of light mediated chemical transformations.

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“…In comparison, the well-known nitrogenase enzyme, which reduces N2 to NH3, was measured electrochemically to have an electron transfer TOF of 14 s -1 . 52 Similarly, we can compare to photocatalytic systems. In an iridium photocatalytic system tuned for CO2 reduction, the highest observed TOF was 0.006 s -1 .…”

Section: Uncertainty In [Qd*] Results In Uncertain Intrinsic Ratementioning

confidence: 99%

Photoinduced charge transfer from quantum dots measured by cyclic voltammetry

Homer

Kuo

Dou

et al. 2022

Preprint

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Measuring and modulating charge-transfer processes at quantum dot interfaces are crucial steps in developing quantum dots as photocatalysts. In this work, cyclic voltammetry under illumination is demonstrated to measure the rate of photoinduced charge transfer from CdS quantum dots by directly probing the changing oxidation states of a library of molecular charge acceptors, including both hole and electron acceptors. The voltammetry data demonstrates the presence of long-lived charge donor states generated by native photodoping of the quantum dots as well as a positive correlation between driving force and rate of charge transfer. Changes to the voltammograms under illumination follow mechanistic predictions from classic zone diagrams and electrochemical modeling allows for measurement of the rate of productive electron transfer. Observed rates for photoinduced charge transfer on the order of 0.1 s-1 are calculated, which are distinct from the picosecond dynamics measured by conventional transient optical spectroscopy methods and are more closely connected to the quantum yield of light mediated chemical transformations.

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Natural and Engineered Electron Transfer of Nitrogenase

Cited by 21 publications

References 171 publications

Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes

Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes

Photoinduced Charge Transfer from Quantum Dots Measured by Cyclic Voltammetry

Photoinduced charge transfer from quantum dots measured by cyclic voltammetry

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