Improved gas sensing properties of copper ferrite nanofibers decorated with polyoxometalate electron acceptor toward ppb-level NO2 detection

In this work, Copper ferrite (CuFe2O4) gas sensitive material was decorated with polyoxometalate (POMs) electron acceptor. A group of CuFe2O4/POMs composite nanofibers with different amount of phosphotungstic acid (PW12) were synthesized by simple and convenient electrospinning technique. The influence of POMs on gas-sensitive performance of ferrite was investigated for the first time. The result shows that the optimal response value toward 5 ppm NO2 gas is 2.63 with fast response/recovery, which is 4.7 times than pure CuFe2O4 sensor. An ultra-low limit-of-detection of 12.86 ppb was also exhibited. The facilitation of sensing performance can be interpreted as the construction of CuFe2O4-PW12 n-n heterojunctions, which can help reduce carriers recombination and effectively separate electron-hole pairs. This paper introduces a new way of developing high sensitivity ferrite-based gas sensors by introducing polyoxometalates as electron acceptors.