Fast catalytic and electrocatalytic oxidation of sodium borohydride on palladium nanoparticles and its application to ultrasensitive DNA detection.
ABSTRACT We report an ultrasensitive DNA sensor using the rapid enhancement of electrocatalytic activity of DNA-conjugated Pd nanoparticles (NPs); the rapid enhancement results from the fast catalytic hydrolysis of NaBH(4) on Pd NPs and subsequent fast hydrogen sorption into Pd NPs.
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ABSTRACT: To gain insight on the mechanistic aspects of the palladium-catalyzed hydrolysis of NaBH(4) in alkaline media, the kinetics of the reaction has been investigated by (11)B NMR (nuclear magnetic resonance) measurements taken at different times during the reaction course. Working with BH(4)(-) concentration in the range 0.05-0.1 M and with a [substrate]/[catalyst] molar ratio of 0.03-0.11, hydrolysis has been found to follow a first-order kinetic dependence from concentration of both the substrate and the catalyst (Pd/C 10 wt %). We followed the reaction of NaBH(4) and its perdeuterated analogue NaBD(4) in H(2)O, in D(2)O and H(2)O/D(2)O mixtures. When the process was carried out in D(2)O, deuterium incorporation in BH(4)(-) afforded BH(4)(-)(n)D(n)(-) (n = 1, 2, 3, 4) species, and a competition between hydrolysis and hydrogen/deuterium exchange processes was observed. By fitting the kinetics NMR data by nonlinear least-squares regression techniques, the rate constants of the elementary steps involved in the palladium-catalyzed borohydride hydrolysis have been evaluated. Such a regression analysis was performed on a reaction scheme wherein the starting reactant BH(4)(-) is allowed both to reversibly exchange hydrogen with deuterium atoms of D(2)O and to irreversibly hydrolyze into borohydroxy species B(OD)(4)(-). In contrast to acid-catalyzed hydrolysis of sodium borohydride, our results indicate that in the palladium-catalyzed process the rate constants of the exchange processes are higher than those of the corresponding hydrolysis reactions.The Journal of Physical Chemistry B 09/2006; 110(34):17024-33. · 3.61 Impact Factor
- Journal of the American Chemical Society 03/2008; 130(6):1828-9. · 10.68 Impact Factor
Article: Nanostructures in biodiagnostics.Chemical Reviews 05/2005; 105(4):1547-62. · 41.30 Impact Factor