Amperometric Nitrite-Ion Sensor Based on Electrodeposited Sm-Based Perovskite-Type Oxide Thick-Film Electrode

Abstract

Perovskite-type oxide SmBO 3 (B = Cr, Mn, Fe, Co) powders were prepared by a polymer precursor method at 750 °С and systematically investigated for electrochemical sensing properties for NO 2 − . The SmBO 3 -modified carbon-felt electrodes could be prepared by an electrophoretic deposition (EPD) method without sintering. Among the oxide deposited electrodes, the SmFeO 3 modified electrode showed the highest sensitivity to NO 2 − with 11.9 mA M −1 cm −2 and a linear sensing range between 5.0 × 10 −5 and 1.0 × 10 −3 M at +0.85 V vs Ag / AgCl with high selectivity for NO 2 − and no response to most other anions. A good correlation was observed between electrochemical activity toward nitrite-ion oxidation and oxygen adsorption properties of the oxides.

Stabilizing Double Perovskite for Effective Bifunctional Oxygen Electrocatalysis in Alkaline Conditions

“…Both of them present e g orbital fillings that are critical in oxygen electrocatalysis Figure b,c illustrates the Fe 2p and Mn 2p core-level spectra of PBCMF-1, which could be deconvoluted into several characteristic subpeaks of Mn 2+ /​Mn 3+ /​Mn 4+ and Fe 3+ /​Fe 4+ . , The calculated average valences of Mn and Fe were 3.03 and 3.40, respectively, from which we can also calculate the 3−δ value in PBCMF-1. It is found that the calculated 3−δ value was in good agreement with the one obtained from the iodometric titration analysis (Table S5), which in turn proves that the e g occupancies obtained from the XPS survey are reliable.…”