Electrospun copper-doped tungsten oxide nanowires for triethylamine gas sensing

One-dimensional (1D) Cu-doped WO3 nanowires (NWs) were synthesized through the electrospinning process and calcination treatment. Taking the doping amount of 5% for example, the average length and diameter of the prepared 1D NWs were 15 μm and 150 nm, respectively. One part of the doped Cu2+ occupied the position of W6+ in the WO3 lattice, and the other part separated out Cu2O/CuO phases, forming p–n heterojunctions with WO3, during the high-temperature calcination. The gas-sensing test results demonstrated that Cu2+ doping significantly improved the material's gas-sensitive properties, and the 5% Cu/WO3 NWs exhibited the best performance. Specifically speaking, the response of 5% Cu/WO3 NWs to 100 ppm triethylamine (TEA) at 180 °C was 108, and the response time was 33 s, both of which were superior to those of pristine WO3 NWs (10, 60 s) at 220 °C. Additionally, the 5% Cu/WO3 NWs based sensor displayed a good TEA selectivity. In addition to TEA, its second-most sensitive gas was acetone, for which the response could reach 28, but still was only a third of that for TEA. Finally, the theory explaining the sensing mechanism was proposed based on the related characterization results.