Search

Extensive research has been devoted to the development of advanced oxygen reduction reaction (ORR) catalysts with functionally diverse active sites. Herein, we show a smart approach to advancing the ORR catalytic activity of a 3D porous perovskite. The facile oxidative-reductive-oxidative (O-R-O) thermal treatment cycle executed on Ag doped LaFeO 3 could stepwise switch on three different reaction sites (exsolved Ag-NPs, oxygen deficiency and Fe 4+ with optimal electron configuration) for ORR. Detailed characterizations illustrate that the ORR activity is basically derived from the hierarchically porous scaffold which provides a large surface area and enough pore volumes for mass and ion diffusion. More importantly, the unique synergistic effects among three separate kinds of reaction sites endow the speed-up of oxygen adsorption, activation and O 2− transportation. The exemplified results set out new design principles for the optimization of alternative catalysts. [ABSTRACT FROM AUTHOR]

In this paper, a nonenzymatic glucose biosensor based on perovskite LaTiO3–Ag0.2(LTA) modified electrode was presented. The morphology and the composition of the perovskite LaTiO3–Ag0.2 nanomaterials were characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. The LaTiO3–Ag0.2(LTA) composite was investigated by electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimal conditions, CV and chronoamperometry (I-t) study revealed that, compared with the bare glassy carbon electrode (GCE), the modified electrode showed a remarkable increase in the efficiency of the electrocatalytic oxidation of glucose, starting at around +0.70V (vs. Ag/AgCl). The prepared sensor exhibited a high sensitivity of 784.14µAmM−1 cm−2, a low detection limit of 2.1×10−7 M and a wide linear range from 2.5µM to 4mM (R=0.9997). More importantly, the LTA modified electrode was also relatively insensitive to commonly interfering species such as ascorbic acid (AA), uric acid (UA), dopamine (DA) in high potential. Moreover, the nonenzymatic sensor was applied to the determination of glucose in human serum samples and the results were in good agreement with clinical data. Electrodes modified with perovskite nanomaterials are highly promising for nonenzymatic electrochemical detection of glucose because of their high sensitivity, fast response, excellent stability and good reproducibility. [ABSTRACT FROM AUTHOR]