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Showing 1 to 20 of 22 for “"Proton reduction"”.
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Fabrication of Chemically Modified Nanometer-sized Gold Electrodes and Their Application in Electrocatalysis at Pt Nanoparticles.
<p>Hydrogen evolution via proton reduction occurs at a high rate at the surface of Pt than at Au electrodes. Using cyclic voltammetry, chemically modified nanometer-sized Au electrodes, prepared by the Laser-Assisted Puller Method, were employed to examine current amplification by electrocalysis at …
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Carbon nitride for solar H2 production coupled to organic chemical transformations
… harvesters, to couple alcohol oxidation with proton reduction, in the presence of a Ni-based molecular catalyst. This system operated in a single compartment while the oxidation and reduction products were collected in the solution and gaseous phases, respectively, demonstrating a closed redox …
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Ligand field considerations for the reactivity of high valent metal-oxo complexes and of bimetallic HX splitting photocatalysts
… HX splitting behavior. The complex photoreduces protons but degrades quickly. Rational ligand modifications afford an indefinitely stable proton reduction photocatalyst. Upon proton reduction from hydrohalic acid, valence isomers of a tetrachloride product were isolated. The efficiencies of …
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Hydrogen in transition metal doped transparent conductive oxide SnO₂
… also to be the best for removing hydrogen via proton reduction and hydrogen evolution from their surfaces due to the relatively high electron concentration they can have. Especially, W-doped is also found to perform best as a hydrogen blocker at all temperature range due to its ability to block …
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Azotobacter vinelandii nitrogenase: role of the MoFe protein α-subunit histidine-195 residue in catalysis
… can reach the redox state necessary for N₂ reduction. Although, N₂ is not a substrate for the altered MoFe protein, it is an inhibitor of both acetylene and proton reduction, both of which are otherwise effectively reduced by the altered MoFe protein. This result provides evidence that N₂ …
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Metabolic and molecular responses to interspecies hydrogen transfer between Ruminococcus albus and Wolinella succinogenes
… [FeFe]-hydrogenase, HydABC, couples proton reduction using nicotinamide adenine dinucleotide (NADH) to proton reduction using reduced ferredoxin (Fdred), producing molecular hydrogen: 3 H+ + NADH + Fdred → 2 H2 + NAD+ + Fdox. HydA2, a ferredoxin-dependent [FeFe]-hydrogenase, reduces …
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Small molecule mimics of hydrogenase enzymes: synthesis, protonation, and electrocatalysis
… enzymes called hydrogenases, which catalyze the reduction of protons to dihydrogen, as well as the reverse reaction. The active sites of the two most prevalent hydrogenases contain NiFe or FeFe cores, bound to thiolates, cyanide, and carbon monoxide ligands. These enzymes are also rich in Fe-S …
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Anaerobic biodegradation of selected organic compounds with and without inhibition of sulfate reducing bacteria
… Addition of molybdate to inhibit sulfate reduction increased the degradation rates more for compounds which may require hydrogen in a structural position (2,4-dichlorophenol, MTBE) than those which require hydrogen for proton reduction (methanol). Biodegradation or recalcitrant compounds …
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The chemistry of transition metal complexes related to solar energy storage : H₂ production and small molecule (CO₂ and HX; X = Cl, Br) chemistry.
… ligands, can catalyze electrochemical proton reduction, a half reaction of water splitting to H₂/O₂ by electricity generated by sunlight. The strategy for designing efficient molecular catalysts were explored by introducing a Hangman scaffold into metallomacrocyles. The study exhibits …
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New Polyazine-Bridged Ru(II),Rh(III) and Ru(II),Rh(I) Supramolecular Photocatalysts for Water Reduction to Hydrogen Applicable for Solar Energy Conversion and Mechanistic Investigation of the Photocatalytic Cycle
… supramolecular photocatalysts for water reduction to H2 and provide mechanistic insights into the catalytic cycle. Two member of a new RuII,RhIII motifs with only one Rh-'Cl bond, [(bpy)2Ru(dpp)RhCl(tpy)](PF6)4 ( bpy = 2,2'-bipyridine, tpy = 2,2':6,2"-terpyridine) and …
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Hydrogen production from model complexes of the [FeFe]- and [NiFe]-hydrogenase active sites
… predominately function to produce hydrogen from protons and electrons, while the [NiFe]-hydrogenases function to oxidize hydrogen. The active sites of both enzymes contain first-row transition metals and biologically exotic ligands. When assayed for their rates and efficiencies of hydrogen …
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Molecular electrocatalysis of hydrogen evolution: catalytic design studied by density functional theory
… molecular hydrogen evolving electrocatalysts. Reduction potentials and pKa’s were calculated for a variety of complexes with density functional theory in conjunction with appropriate experimental references in order to characterize the thermodynamics of the free energy of reaction for proton …
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Solar Driven Hydrogen Generation with Dye-Sensitised CuCrO2 Photocathodes
… photocathode capable of photoelectrochemical proton reduction under solar irradiation. Hydrothermal synthesis of CuCrO2 nanoparticles enabled the development of nanostructured inverse opal electrodes (IO-CuCrO2) using a bottom-up templating method (Chapter 4). These electrodes were explored as …
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Hydrogen entry in Zircaloy-4 fuel cladding : an electrochemical study
… Water Reactors (PWRs): are the adsorbed protons incorporated into the oxide and eventually the metal, or are they evolved into molecular hydrogen and released into the coolant? Water chemistry modeling was used to understand effects of radiolysis and CRUD. Density functional theory (DFT) …
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Mixed-valence bimetallic dithiolates of iron, cobalt, and nickel and their relevance to the hydrogenases
… (H2ases) to efficiently interconvert protons and electrons with dihydrogen. Though this is one of the simplest possible reactions, it is of utmost importance for countless microorganisms. The performance of these enzymes exceeds that of the leading artificial catalyst used by humans: …
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Metal-organic frameworks and porous composites for photocatalytic and sensing applications
… which can absorb light energy, leading to the reduction of water to hydrogen with no carbon emissions. The current research used densified, monolithic MOFs (monoMOF) in contrast to conventional and widely reported powder MOFs. Such monoliths (prepared without binders or under high pressure) are …
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Optical and structural characterization of metal oxides and carbon nitride compounds for the development of organic/inorganic hybrid systems
… band edge not sufficiently negative to promote proton reduction (limited photocatalytic activity). The introduction of doping elements in the MO matrix to reduce these limitations can have the drawbacks of the new defects generation at the surface and/or in the bulk. Other limitations can be …
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Molecular Hybrid Photocathodes Based on Silicon for Solar Fuel Synthesis
… energy carrier (e.g. H$_{2}$ and CO$_{2}$-reduction products from H$_{2}$O and CO$_{2}$). However, molecular catalyst-based photocathodes remain scarcely reported and typically suffer from low efficiencies and/or stabilities due to inadequate strategies for interfacing the molecular …
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Coordination chemistry of unusual oxidation states of nickel and palladium relevant to homogeneous catalysis
… molecule activation reactions – particularly the proton and carbon dioxide reduction reactions. Key contributions include the development of a small-molecule mimic of the redox-active Ni center of [NiFe] hydrogenase. The small-molecule model was shown to switch between NiI and NiIII via a C-H …
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Semi-Artificial Photoelectrochemistry through Perovskite Integration and Elucidation of the Local Environment
… resistance to H₂, and intrinsic bias for proton reduction. The biocatalyst was immobilised on a hierarchical inverse opal mesoporous TiO₂ scaffold, and combined with the perovskite by a Ti foil platform, which provided structural support and enhanced moisture protection of the …
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