Electrochemical Sulfite-Ion Sensor Using Sm2CuO4-Based Layered Perovskite-Type Oxide Thick Film

Sm2-xCexBO4 (x = 0, 0.1; B = Fe, Cu) thick films were prepared by an electrophoretic deposition method and applied as sulfite-ion (SO32-) sensors. Among the oxides, Sm1.9Ce0.1CuO4 showed good amperometric response to sulfite ions in the ion concentration range between 1.0 x 10(-5) and 1.0 x 10(-4) M at 30 degrees C. The applied potential to the electrode should be one of the key factors of high selectivity, and the relatively low potential of +0.2 V versus Ag/AgCl was found to be optimal for the detection of sulfite ions. Good sulfite-ion sensing should be enabled by Cu+ in Sm1.9Ce0.1CuO4 where SO32- is easily adsorbed. (C) 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.