Microheterogeneous electrocatalytic chiral recognition at monoclinic vanadium-doped zirconias: enantioselective detection of glucose.
Synthetic tetragonal and monoclinic vanadium-doped zirconias (t- and m-VxZr1-xO2, 0.005 < x < 0.150) exert an effective catalytic effect toward the electrochemical oxidation of glucose in aqueous alkaline media. The catalytic effect of monoclinic specimens attached to carbon and fluorine-doped tin oxide electrodes exhibits a remarkable enantioselectivity, so that catalytic currents for the oxidation of L-glucose at +0.92 V vs AgCl/Ag are considerably larger than those obtained for the oxidation of D-glucose. This enantioselectivity can be associated with the existence of a noncentrosymmetric coordination of vanadium centers in the monoclinic crystalline form of zirconia. From the electrochemical results, it can be suggested that the electrocatalytic mechanism includes the formation of glucose-vanadium surface adducts and electron transfer between catalytic centers and the substrate. The interference from chloride ions in the electrocatalytic process is significantly decreased by covering the zirconia particles with a layer of amorphous silica. These results propose that incorporation of catalytically active centers into nonsentrosymmetric sites of inorganic crystalline materials can be taken as a plausible strategy for chiral recognition via electrocatalysis.
Doménech
Antonio
A
Departament de Química Analítica, Facultat de Química, Facultat de Química, Universitat de València, Doctor Moliner 50, 46100, Burjassot, Valencia, Spain. antonio.domenech@uv.es
Alarcón
Javier
J
D002138:Calibration; D002384:Catalysis; D004563:Electrochemistry; D004583:Electrons; D005947:Glucose / Q000032:analysis* / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D014639:Vanadium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
D014639:Vanadium; D015040:Zirconium; D005947:Glucose