Gas sensing and electrochemical properties of rare earthferrite, LnFeO3 (Ln = Nd, Sm)

In this paper, nanostructured perovskite-type LnFeO(3) (Ln = Nd, Sm) oxides were synthesized by thermal treatment method (TTM). Characterization analysis conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-Raman spectroscopy, have confirmed the perovskite structure of the synthesized nanomaterials. To study the effects of Nd and Sm lanthanides substitution at the A-site on the chemical sensing performance, conductometric and electrochemical sensors based on the synthesized LnFeO3 samples were fabricated. LnFeO3-based conductometric and electrochemical sensors were tested for acetone and dopamine sensing, respectively. The data revealed that Nd and Sm in the A-position lead to a significant influence in the gas sensing and electrochemical properties of perovskite LnFeO(3) samples. In particular, it has been demonstrated the good gas sensing characteristics of SmFeO3 for acetone gas (Response = R/R-0= 8.3-20 ppm acetone at 200 degrees C), whereas NdFeO3 displayed better performance as electrode for the electrochemical detection of dopamine reaching a low detection limit (LOD) of 270 nM at S/N = 3. The electrical and electrochemical characteristics of the perovskite LnFeO(3) samples were discussed in detail with respect to their chemical composition and microstructure.