Zhiying Li

A novel room temperature ionic liquid sol–gel matrix for amperometric biosensor application

A novel type of ionic liquid (IL) sol–gel hybrid material was developed for amperometric biosensor application. This material was prepared by the hydrolysis of tetraethyl orthosilicate in a 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4−) solution. The viscous IL prevented the cracking of the sol–gel derived glasses. Horseradish peroxidase (HRP) was immobilized in the hybrid material for the production of an amperometric hydrogen peroxide biosensor. The IL sol–gel enzyme electrodes retained the high activity of HRP and provided long-term stability of HRP in storage. The morphology of the matrix-containing enzyme was characterized by scanning electron microscopy. The characteristics of the biosensor were also investigated by cyclic voltammetry and chronoamperometry. In the presence of ferrocene as a mediator, the biosensor exhibited an excellent stability and sensitivity, and the linear calibration ranged from 0.02 to 0.26 mM with a detection of 1.1 µM. The apparent Michaelis–Menten constant of the immobilized HRP was 2.0 mM.

Highly active horseradish peroxidase immobilized in 1-butyl-3-methylimidazolium tetrafluoroborate room-temperature ionic liquid based sol–gel host materials

Dramatically enhanced activity and excellent thermal stability of horseradish peroxidase were obtained by immobilizing it in a 1-butyl-3-methylimidazolium tetrafluoroborate room-temperature ionic liquid based sol-gel matrix.

High surface area nanoporous platinum: facile fabrication and electrocatalytic activity

In this paper, nanoporous platinum films with an enhanced surface area were obtained through a facile route by selective anodic dissolution of Cu from PtCu alloy. A homogeneous PtCu alloy was electrochemically deposited at a glassy carbon electrode at room temperature, then Cu was electrochemically etched from the PtCu alloy resulting in the fabrication of a nanoporous platinum film with a much higher surface area. The surface area of the dealloyed nanoporous platinum film was highly enhanced by up to 500 times compared with that of a polycrystalline platinum electrode. This nanoporous platinum film exhibited high stability and remarkable catalytic activity for oxygen electro-reduction and methanol electro-oxidation, with promising applications in fuel cells and biosensors, etc.

Electrodeposition of Platinum in Room-Temperature Ionic Liquids and Electrocatalytic Effect on Electro-oxidation of Methanol

The use of room-temperature ionic liquids (RTILs) as green media for electrochemical application is desirable. The electrodeposition behavior of platinum was investigated at a glassy carbon electrode in hydrophilic l-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF 4 ) and hydrophobic 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ) RTILs containing chloroplatinic acid hexahydrate by cyclic voltammetric and potentiostatic transient techniques and atomic force microscopy (AFM). For comparison, the electrodeposition of platinum in HClO 4 aqueous solution was also investigated. The cyclic voltammograms after the first scan circle in these media were different from each other, showing the obvious media effect on the electrochemical behavior of chloroplatinic acid hexahydrate. The analysis of the experimental current transients showed that the electrodeposition process of platinum in these media was characteristic of three-dimensional progressive nucleation with diffusion-controlled hemispherical growth. AFM showed that the uniform, shiny electrodeposits of platinum obtained in BMIMBF 4 and BMIMPF 6 RTILs were fairly dense and that the separate spherical nanoclusters were less than 100 nm. For the electro-oxidation of methanol in H 2 SO 4 solution, the platinum films prepared in both BMIMBF 4 and BMIMPF 6 RTILs exhibited high electrocatalytic current densities.