Nb₂O₅ Microcolumns for Ethanol Sensing.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Niobium oxide (Nb2O5) is a promising material for gas sensing applications.
• Developing cost-effective synthesis methods for nanostructured Nb2O5 is crucial.
• Gas sensors require high selectivity, sensitivity, and stability under various conditions.

Purpose of the Study:

• To synthesize pseudohexagonal Nb2O5 microcolumns using a hydrothermal method.
• To fabricate and characterize conductometry sensors based on Nb2O5 microcolumns.
• To evaluate the gas sensing performance of Nb2O5 sensors for ethanol detection.

Main Methods:

• Hydrothermal synthesis of Nb2O5 microcolumns at 180 °C for 30 min, followed by calcination at 500 °C.
• Characterization using Raman spectroscopy and High-Resolution Transmission Electron Microscopy (HRTEM).
• Fabrication of conductometry sensors by drop-casting Nb2O5 microcolumns on Pt electrodes.

Main Results:

• Raman spectroscopy confirmed the pseudohexagonal Nb2O5 structure with characteristic peaks.
• HRTEM revealed specific inter-lattice distances.
• Sensors demonstrated excellent selectivity for ethanol (C2H5OH) with a response of ΔG/G = 2.51 for 10 ppm.
• Optimal operating temperature was 500 °C in dry air.
• Sensors exhibited high repeatability and strong humidity resistance (up to 90% RH).

Conclusions:

• Cost-effective hydrothermal synthesis yields pseudohexagonal Nb2O5 microcolumns suitable for gas sensing.
• Nb2O5 microcolumn-based sensors offer excellent selectivity and stability for ethanol detection.
• The nanoporous structure and high operating temperature contribute to the sensors' humidity resistance and overall performance.