Huiqin Yao1,2, Ben Liu1, Islam M Mosa2,3, Itti Bist2, Jie He2,4, James F Rusling2,4,5,6. 1. Department of Chemistry, Ningxia Medical University, Yinchuan 750004 (China). 2. Department of Chemistry and GEMS Center, University of Connecticut, Storrs, CT 06269 (USA). 3. Department of Chemistry, Tanta University, Tanta, 31527 (Egypt). 4. Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (USA). 5. Department of Surgery and Neag Cancer Center, University of Connecticut Health Center, Farmington, CT 06232 (USA). 6. School of Chemistry, National University of Ireland at Galway, H91 Galway (Ireland).
Abstract
Electrocatalytic properties of ligand-free gold nanoclusters (AuNCs, <2 nm) grown on nitrided carbon supports (denoted as AuNCs@N-C) were evaluated for the oxidation of representative organic molecules including alcohols, an amine, and deoxyguanosine in oligonucleotides. AuNCs@N-C catalysts were incorporated into films of architecture {PDDA/AuNCs@N-C} n by using layer-by-layer assembly with oppositely charged poly(diallyldimethylammonium) (PDDA) on pyrolytic graphite (PG) electrodes. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to survey the electrocatalytic properties of these AuNCs@N-C films. Ligand-free AuNCs in these films demonstrated excellent electrocatalytic oxidation activity with maximum peak currents and the lowest potentials for oxidizing ethanol, propanol, and tripropylamine (TprA) compared to controls with Au-surface capping agents or to larger sized Au nanocrystals on the nitrided carbon supports. EIS kinetic studies showed that ligand-free AuNCs films have the smallest charge-transfer resistance, largest electrochemically active surface area, and largest apparent standard rate constants, as compared to the control films for all compounds examined. DNA films on AuNCs@N-C were oxidized at deoxyguanosine moieties with good catalytic activity that depended on charge transport within the films.
Electrocatalytic properties of ligand-free gold nanoclusters (n class="Chemical">AuNCs, <2 nm) grown on nitrided carbon supports (denoted as AuNCs@N-C) were evaluated for the oxidation of representative organic molecules including alcohols, an amine, and deoxyguanosine in oligonucleotides. AuNCs@N-C catalysts were incorporated into films of architecture {PDDA/AuNCs@N-C} n by using layer-by-layer assembly with oppositely charged poly(diallyldimethylammonium) (PDDA) on pyrolytic graphite (PG) electrodes. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to survey the electrocatalytic properties of these AuNCs@N-C films. Ligand-free AuNCs in these films demonstrated excellent electrocatalytic oxidation activity with maximum peak currents and the lowest potentials for oxidizing ethanol, propanol, and tripropylamine (TprA) compared to controls with Au-surface capping agents or to larger sized Au nanocrystals on the nitrided carbon supports. EIS kinetic studies showed that ligand-free AuNCs films have the smallest charge-transfer resistance, largest electrochemically active surface area, and largest apparent standard rate constants, as compared to the control films for all compounds examined. DNA films on AuNCs@N-C were oxidized at deoxyguanosine moieties with good catalytic activity that depended on charge transport within the films.
Authors: Hanne Falsig; Britt Hvolbaek; Iben S Kristensen; Tao Jiang; Thomas Bligaard; Claus H Christensen; Jens K Nørskov Journal: Angew Chem Int Ed Engl Date: 2008 Impact factor: 15.336