Neodymium cobalt oxide as a chemical sensor

Highlights

• NdCoO₃ materials is successfully fabricated as acetone chemical sensor.

• Analytical performances of acetone chemical sensor are investigated by reliable I–V method in terms of sensitivity, linearity, and detection limit in short response time.

Abstract

Chemical sensing and electrical transport properties of neodymium coblate, NdCoO₃, was investigated in this work. It was prepared by using co-precipitation method. Pure neodymium chloride and cobalt chloride were mixing in the presence of sodium hydroxide and the obtained co-precipitated powder was calcined at 850 and 1000 °C. The synthesized composites, as-grown (NdCoO₃-I), calcined at 850 °C (NdCoO₃-II), and calcined at 1000 °C (NdCoO₃-III) were studied in details in terms of their morphological and structural properties. The X-ray analysis confirmed that the synthesized products are well crystalline possessing single phase orthorhombic crystal system of space group Pbnm (62). The crystallite size of NdCoO₃-I, NdCoO₃-II, and NdCoO₃-III is 22, 111, and 338 nm, respectively which reflect that crystallite size is increasing with increase in firing temperature. The DC resistivity was measured as a function of temperature in the temperature range from room temperature up to 200 °C. All NdCoO₃ are semiconductor in this range of temperature but showed different activation energy which strongly depends on the crystallite size of the products. The activation energy decreased with increase in crystallite size, 0.798, 0.414 and 0.371 eV for NdCoO₃-I, NdCoO₃-II, and NdCoO₃-III, respectively. Thus resistivity increases with increase in crystallite size of NdCoO₃. All NdCoO₃ products were tested as chemical sensor for acetone by electrochemical approaches and showed excellent sensitivity. Among the NdCoO₃ samples, NdCoO₃-III showed the highest sensitivity (3.4722 μAcm⁻² mM⁻¹) compared to other compositions and gradually decreased to 3.2407 μAcm⁻² mM⁻¹ with decreasing the crystallite size of NdCoO₃-II. It is also observed that the sensitivity drastically decreased to 0.76253 μAcm⁻² mM⁻¹ in the case of NdCoO₃-I. It is introduced an efficient route for the detection of environmental unsafe chemicals by electrochemical approach for the safety of healthcare and environmental fields in broad scales.