Nanofiber Production Equipment| Efficient detection of triethylamine byInzOз@C0304 core-shell nanofiberssynthesized by coaxial electrospinning

Professor Song Peng from University of Jinan: Core-Shell Structured Nanofibers for Efficient Triethylamine Gas Detection

Volatile organic compounds like triethylamine (TEA) are widely used in organic chemical synthesis industries as pesticides, textiles, preservatives, and catalysts. However, TEA exposure can affect human health, causing eye, skin, and respiratory irritation, with long-term exposure potentially increasing risks of liver and lung cancer. Additionally, TEA is a natural substance released during the decomposition of fish and shellfish, serving as an indicator of seafood freshness. Therefore, rapid and effective TEA gas detection is crucial for ensuring industrial safety and human health.

Recently, Professor Song Peng's team at University of Jinan published their latest research "Efficient detection of triethylamine by In2O3@Co3O4 core-shell nanofibers synthesized by coaxial electrospinning" in Sensors and Actuators B: Chemical. The researchers prepared In2O3@Co3O4 core-shell nanofibers (CSNFs) with heterointerfaces using coaxial electrospinning technology. Compared to pure In2O3 NFs, the In2O3@Co3O4 CSNFs gas sensor demonstrated superior gas-sensing performance toward TEA, providing valuable references for designing high-performance sensors and promoting technological innovation in sensor development.

Fig. 1: Microstructure analysis of In2O3 NFs and In2O3@Co3O4 CSNFs

Figure 1(a) shows TEM images of pure In2O3 NFs prepared by uniaxial electrospinning, revealing single-fiber structures with uniform texture, complete morphology, and diameters around 100 nm. Figure 1(b) displays TEM images of In2O3@Co3O4 CSNFs, clearly showing core-shell structures composed of numerous grains, with rough and porous fiber surfaces. HRTEM measurements identified lattice spacings of 0.292 nm and 0.243 nm, corresponding to In2O3 (222) and Co3O4 (311) crystal planes, respectively. Figure 1(d) presents the energy-dispersive spectrum, showing homogeneous distribution of In, Co, and O, confirming successful synthesis of In2O3@Co3O4 CSNFs composites.

Fig. 2: Crystal structures of In2O3 NFs and In2O3@Co3O4 CSNFs

As shown in Figure 2(a), all diffraction peaks were sharp without impurities, indicating excellent crystallinity and high purity. Comparing pure In2O3 NFs and In2O3@Co3O4 CSNFs, the composite's pattern contained all In2O3 diffraction peaks plus an additional peak near 2θ=36.76° (marked by red circle), corresponding to Co3O4 (311) plane (JCPDS: 73-1701), consistent with HRTEM results and further verifying successful preparation of high-purity p-n heterojunction composites.

Fig. 3: Gas-sensing performance of In2O3 NFs and In2O3@Co3O4 CSNFs sensors

Gas-sensing tests showed the optimal operating temperature of In2O3@Co3O4 CSNFs gas sensors decreased from 160°C to 120°C, partially addressing the high-temperature limitation of metal oxide gas sensors. At 120°C, the sensor's response to 50 ppm TEA reached 40.5 - 13.5 times higher than pure In2O3 nanofibers. Additionally, the sensor exhibited stable reproducibility, fast response/recovery (7s/4s), and excellent selectivity, attributed to the porous core-shell structure's permeability and electron transfer at p-n heterojunctions.

Fig. 4: DFT calculations of TEA adsorption energy on In2O3 NFs and In2O3@Co3O4 CSNFs

DFT calculations analyzed TEA adsorption energy on sensing materials. Optimized adsorption models for TEA on pure In2O3 NFs and In2O3@Co3O4 CSNFs showed adsorption energies of -0.361 eV and -1.653 eV, respectively. The larger absolute value for the composite indicates stronger interaction with TEA, enhancing adsorption stability, which improves sensor response and lifespan.

Paper link: https://doi.org/10.1016/j.snb.2025.137831