From Hydrogenases to Noble Metal–Free Catalytic Nanomaterials for H
            <sub>2</sub>
            Production and Uptake

Goff, Alan Le; Artero, Vincent; Jousselme, Bruno; Tran, Phong D.; Guillet, Nicolas; Metayé, Romain; Fihri, Aziz; Palacin, Serge; Fontecave, Marc

doi:10.1126/science.1179773

Cited by 910 publications

(692 citation statements)

References 26 publications

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“…For example, nanomedicine potentially provides solutions for early diagnosis and personalized medicine for the treatment of complex diseases such as cancer and metabolic disorders. Nanotechnologies also provide a potential solution to social challenges, such as energy shortages 2,3 and environmental deterioration. 4 As of March 2011, there were 1317 nanotechnology-based consumer products on the market, including food containers, fabrics, sports equipment, antibiotic reagents, and electronic components.…”

Section: Introductionmentioning

confidence: 99%

Perturbation of physiological systems by nanoparticles

et al. 2014

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Nanotechnology is having a tremendous impact on our society. However, societal concerns about human safety under nanoparticle exposure may derail the broad application of this promising technology. Nanoparticles may enter the human body via various routes, including respiratory pathways, the digestive tract, skin contact, intravenous injection, and implantation. After absorption, nanoparticles are carried to distal organs by the bloodstream and the lymphatic system. During this process, they interact with biological molecules and perturb physiological systems. Although some ingested or absorbed nanoparticles are eliminated, others remain in the body for a long time. The human body is composed of multiple systems that work together to maintain physiological homeostasis. The unexpected invasion of these systems by nanoparticles disturbs normal cell signaling, impairs cell and organ functions, and may even cause pathological disorders. This review examines the comprehensive health risks of exposure to nanoparticles by discussing how nanoparticles perturb various physiological systems as revealed by animal studies. The potential toxicity of nanoparticles to each physiological system and the implications of disrupting the balance among systems are emphasized.

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Section: Introductionmentioning

confidence: 99%

Perturbation of physiological systems by nanoparticles

et al. 2014

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“…Hydrogenase active sites contain iron, nickel (in one class), thiolates, CO and CN − (1), all abundant and inexpensive components, and their H 2 uptake efficiencies compare well with those of expensive traditional catalysts like Pt (4). Impressive progress has been made recently in the field of bioinspired chemistry, and some synthetic catalysts equal or even surpass enzymes in hydrogen evolution activity (5). A recent example is a complex that combines features of both [NiFe]-and [FeFe]-hydrogenases, containing a nickel ion and pendant amines (6).…”

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confidence: 99%

X-ray crystallographic and computational studies of the O ₂ -tolerant [NiFe]-hydrogenase 1 from Escherichia coli

Volbeda

Amara

Darnault

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

192

269

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The crystal structure of the membrane-bound O 2 -tolerant [NiFe]-hydrogenase 1 from Escherichia coli (EcHyd-1) has been solved in three different states: as-isolated, H 2 -reduced, and chemically oxidized. As very recently reported for similar enzymes from Ralstonia eutropha and Hydrogenovibrio marinus, two supernumerary Cys residues coordinate the proximal [FeS] cluster in EcHyd-1, which lacks one of the inorganic sulfide ligands. We find that the as-isolated, aerobically purified species contains a mixture of at least two conformations for one of the cluster iron ions and Glu76. In one of them, Glu76 and the iron occupy positions that are similar to those found in O 2 -sensitive [NiFe]-hydrogenases. In the other conformation, this iron binds, besides three sulfur ligands, the amide N from Cys20 and one Oϵ of Glu76. Our calculations show that oxidation of this unique iron generates the high-potential form of the proximal cluster. The structural rearrangement caused by oxidation is confirmed by our H 2 -reduced and oxidized EcHyd-1 structures. Thus, thanks to the peculiar coordination of the unique iron, the proximal cluster can contribute two successive electrons to secure complete reduction of O 2 to H 2 O at the active site. The two observed conformations of Glu76 are consistent with this residue playing the role of a base to deprotonate the amide moiety of Cys20 upon iron binding and transfer the resulting proton away, thus allowing the second oxidation to be electroneutral. The comparison of our structures also shows the existence of a dynamic chain of water molecules, resulting from O 2 reduction, located near the active site.[4Fe-3S] cluster | membrane-bound hydrogenase | Mössbauer spectroscopy | QM/MM | structure/function relationships

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“…Progress has been made recently in identifying catalysts capable of producing hydrogen from acidic media using either small molecule mimics of hydrogenase active sites or other synthetic systems (3)(4)(5)(6)(7)(8)(9)(10)(11).…”

mentioning

confidence: 99%

“…It follows that immobilization onto an electrode surface would disfavor this pathway (7,22,23). It is of interest in this context that binuclear analogues of many catalysts that rely on bimetallic interactions show enhanced activity when compared to monomeric species, examples include certain Ru and Os diporphyrin H 2 evolving catalysts with cofacial orientation (24,25).…”

mentioning

confidence: 99%

Catalytic hydrogen evolution from a covalently linked dicobaloxime

Valdez

Dempsey

Brunschwig

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

103

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A dicobaloxime in which monomeric Co(III) units are linked by an octamethylene bis(glyoxime) catalyzes the reduction of protons from p-toluenesulfonic acid as evidenced by electrocatalytic waves at −0.4 V vs. the saturated calomel electrode (SCE) in acetonitrile solutions. Rates of hydrogen evolution were determined from catalytic current peak heights (k app ¼ 1100 AE 70 M −1 s −1 ). Electrochemical experiments reveal no significant enhancement in the rate of H 2 evolution from that of a monomeric analogue: The experimental rate law is first order in catalyst and acid consistent with previous findings for similar mononuclear cobaloximes. Our work suggests that H 2 evolution likely occurs by protonation of reductively generated Co II H rather than homolysis of two Co III H units.hydrogen evolving catalysts | solar fuel E fficient catalytic reduction of protons to dihydrogen is a requirement for one half of a functional solar water splitting system (1, 2). Progress has been made recently in identifying catalysts capable of producing hydrogen from acidic media using either small molecule mimics of hydrogenase active sites or other synthetic systems (3-11).Our work has focused on difluoroboryl-bridged Co II -diglyoxime complexes that catalyze hydrogen evolution at low overpotentials (12)(13)(14)(15). With these complexes, hydrogen evolution is initiated upon reduction to Co I , which then reacts with a proton donor to form a Co III -hydride (Co III H). The Co III H intermediate can either undergo subsequent protonation to release H 2 and a Co III species that is reduced to regenerate the catalyst (heterolytic route) or react with another Co III H to eliminate H 2 by a homolytic route. Alternatively, Co III H can be reduced further to form Co II H, which can react via similar heterolytic or homolytic routes (16). Digital simulations of electrocatalytic waves performed by Hu et al. (17) indicated that the bimolecular homolytic Co III H route is the dominant pathway for hydrogen evolution. Our analysis of electron transfer rates in the catalytic cycle confirmed that the barriers to H 2 evolution associated with this pathway are more favorable than that for protonation of Co III H (17, 18). Recent work in our group examining the mechanism of hydrogen evolution from a photogenerated hydridocobaloxime suggests that hydrogen evolution via protonation of Co II H is favored under certain conditions (Co III H in low concentrations with reducing equivalents in excess) (16). Computational studies reported by 20) and Muckerman (21) suggest that Co II H protonation is a very favorable reaction pathway and that relative fluxes through the homolytic Co III H and heterolytic Co II H channels depend on experimental conditions (relative concentrations of acid and catalyst).In the low-barrier homolytic mechanism, two Co III H species must diffuse together in solution in order to react and release H 2 . It follows that immobilization onto an electrode surface would disfavor this pathway (7,22,23). It is of interest in this context that...

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From Hydrogenases to Noble Metal–Free Catalytic Nanomaterials for H ₂ Production and Uptake

Abstract: International audienc

Cited by 910 publications

References 26 publications

Perturbation of physiological systems by nanoparticles

Perturbation of physiological systems by nanoparticles

X-ray crystallographic and computational studies of the O ₂ -tolerant [NiFe]-hydrogenase 1 from Escherichia coli

Catalytic hydrogen evolution from a covalently linked dicobaloxime

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From Hydrogenases to Noble Metal–Free Catalytic Nanomaterials for H 2 Production and Uptake

Abstract: International audienc

Cited by 910 publications

References 26 publications

Perturbation of physiological systems by nanoparticles

Perturbation of physiological systems by nanoparticles

X-ray crystallographic and computational studies of the O 2 -tolerant [NiFe]-hydrogenase 1 from Escherichia coli

Catalytic hydrogen evolution from a covalently linked dicobaloxime

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Product

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From Hydrogenases to Noble Metal–Free Catalytic Nanomaterials for H ₂ Production and Uptake

X-ray crystallographic and computational studies of the O ₂ -tolerant [NiFe]-hydrogenase 1 from Escherichia coli