An ultrasensitive electrochemiluminescence (ECL) method on the combination of electrochemical parallel catalytic reaction and chemiluminesence signal sensing was proposed for improving ECL analytical characteristics using vanadate(V) as a representative. Vanadate(V) could be electrochemically reduced to generate vanadate(II) which could be chemically oxidized by potassium periodate to regenerate vanadate(V) and give parallel catalytic wave effect. Then, the reduced product of potassium periodate could react with butyl‐rhodamine B to emit a sensitive chemiluminescence signal. The chemiluminescence intensity was correlative with vanadate(V) concentration. The investigation on the electrochemical reaction rate constant (k0) confirmed that the speed of electrochemical reaction was faster than that of the subsequent chemiluminescence reaction. The possibility of the combination of electrochemical parallel catalytic reaction with chemiluminescence signal sensing was proved. The similar ECL behaviors could be observed at zirconia nanowires‐Nafion modified electrode. Because of the separation and enrichment effect of the modified electrode on vanadate(V), the selectivity and sensitivity was further improved greatly. Based on these findings, a new concept on the combination of electrochemical parallel catalytic reaction and chemiluminesence signal sensing was proposed and an ultrasensitive ECL method for the determination of vanadate(V) was developed at zirconia nanowires‐Nafion modified electrode. Under the optimum experimental conditions, the ECL intensity was linear with the concentration of vanadate(V) in the range of 2.0×10?12 mol/L–2.0×10?10 mol/L. The detection limit was 8.0×10?13 mol/L, which was more than 6 orders of magnitude lower than that observed by electrochemical current transduction for electrochemical parallel catalytic reaction at zirconia nanowires‐Nafion modified electrode. 相似文献
High catalytic proficiencies observed for the native and promiscuous reaction of the Pseudomonas aeruginosa arylsulfatase (PAS; the picture shows transition states of the two substrates with corresponding binding constants Ktx) suggest that the trade‐off between high activity and tight specificity can be substantially relaxed.
Adsorption ability and reaction rate are two essential parameters that define the efficiency of a catalyst. Herein, we implement density functional theory (DFT) and report that CO can be oxidized by a pyramidal Cu cluster with an associated reaction barrier Eb=1.317 eV. In this case, our transition state calculations reveal that the barrier can be significantly lowered after superimposing a negative electric field. Moreover, when the field intensity corresponds to F=?0.010 au, the magnitude of Eb=0.698 eV is equivalent to—or lower than—those of typical catalysts such as Pt, Rh, and Pd. The superimposition of a positive field is found to enhance the release of the nascent CO2 molecule. Our study demonstrates that small Cu clusters have better adsorption ability than the corresponding flat surface while the field can be used to enhance the purification of the exhaust gas.相似文献
Noncyclic polyether-amino acid Schiff base con- taining some O and N atoms is a new important bio- logical ligand and it shows some interesting biological properties, such as antibacterial, antiphlogistic, anti- cancer and high catalytic activities[1―3], so the chemi- cal behavior of their transition metal complexes has drawn our attention[4]. We report here the synthesis of the title Cu(II) complex with polyether–phenylalanine Schiff base and its characterization by elemental analysis, I… 相似文献
