title: Langmuir-Blodgett films of pyridyldithio-modified multiwalled carbon nanotubes as a support to immobilize hydrogenase.
abstract: Pyridylthio-modified multiwalled carbon nanotubes (pythio-MWNTs) have been prepared by a reaction of the oxidized MWNTs with S-(2-aminoethylthio)-2-thiopyridine hydrochloride. The obtained pythio-MWNTs nanocomposites formed stable floating monolayers at the air-water interface, which were transferred onto substrate surfaces by the Langmuir-Blodgett (LB) method. Compositions and morphologies of the LB films were characterized by absorption, Raman, X-ray photoelectron spectra as well as by scan electron microscopy and atomic force microscopy. These pythio-MWNTs LB films were then used as a support to immobilize hydrogenase (H(2)ase) to form bionanocomposite of pythio-MWNTs-H(2)ase. Cyclic voltammograms for indium tin oxide electrode covered with the pythio-MWNTs-H(2)ase films were investigated in both Ar and H(2) saturated 0.05 M KCl electrolyte solutions at pH from 4.0 to 9.0. A reversible redox couple of [4Fe-4S](2+/1+) clusters of H(2)ase was recorded when the pH value was 6.0 and 9.0, with reduction and oxidation potentials appearing at about -0.70 and -0.35 V vs Ag/AgCl, respectively. It was revealed that the H(2)ase was of high catalytic activity and strong stability in the LB films of pythio-MWNTs-H(2)ase. Hence, we suggested that the present bionanocomposites could be used as heterogeneous biocatalyst to catalyze reversible reaction between protons and H(2), resulting in potential applications in biohydrogen evolution and H(2) biofuel cells.
authors.affiliation: Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Sun
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Zorin
authors.forename: Dan
authors.initials: D
authors.lastname: Chen
authors.forename: Meng
authors.initials: M
authors.lastname: Chen
authors.forename: Tian-Xi
authors.initials: TX
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Miyake
authors.forename: Dong-Jin
authors.initials: DJ
authors.lastname: Qian
mesh_terms: D056804:Biofuels; D055664:Electrochemical Techniques; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011725:Pyridines
chemical_list: D056804:Biofuels; D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D011725:Pyridines; D006864:Hydrogenase; C029347:2-thiopyridine