title: Direct comparison of the performance of a bio-inspired synthetic nickel catalyst and a [NiFe]-hydrogenase, both covalently attached to electrodes.
abstract: The active site of hydrogenases has been a source of inspiration for the development of molecular catalysts. However, direct comparisons between molecular catalysts and enzymes have not been possible because different techniques are used to evaluate both types of catalysts, minimizing our ability to determine how far we have come in mimicking the enzymatic performance. The catalytic properties of the [Ni(P(Cy) 2 N(Gly) 2 )2 ](2+) complex with the [NiFe]-hydrogenase from Desulfovibrio vulgaris immobilized on a functionalized electrode were compared under identical conditions. At pH 7, the enzyme shows higher activity and lower overpotential with better stability, while at low pH, the molecular catalyst outperforms the enzyme in all respects. This is the first direct comparison of enzymes and molecular complexes, enabling a unique understanding of the benefits and detriments of both systems, and advancing our understanding of the utilization of these bio-inspired complexes in fuel cells.
authors.affiliation: Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr (Germany).
authors.forename: Patricia
authors.initials: P
authors.lastname: Rodriguez-Maciá
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA 99354 (USA).
authors.forename: Arnab
authors.initials: A
authors.lastname: Dutta
authors.affiliation: Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr (Germany).
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lubitz
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA 99354 (USA). wendy.shaw@pnnl.gov.
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Shaw
authors.affiliation: Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr (Germany). olaf.ruediger@cec.mpg.de.
authors.forename: Olaf
authors.initials: O
authors.lastname: Rüdiger
mesh_terms: D055162:Biocatalysis; D004566:Electrodes; D006864:Hydrogenase / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry / Q000378:metabolism*; D009942:Organometallic Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D009942:Organometallic Compounds; D009532:Nickel; C043296:nickel-iron hydrogenase; D006864:Hydrogenase
keywords: enzyme catalysis; hydrogen oxidation; hydrogenases; molecular catalysis; surface-immobilized catalysis