Highly selective detection of NH3 and H2S using the pristine CuO and mesoporous In2O3@CuO multijunctions nanofibers at room temperature

Abstract To further develop sensing materials for the detection of reducing gases like NH 3 and H 2 S and improve their response efficiency and selectivity, mesoporous In 2 O 3 @CuO composite multijunctions nanofibers (ICCNs) was synthesized by an electrospinning approach with a subsequent thermal treatment. Comparison was made with the one-dimensional (1D) pristine CuO multijunctions nanofibers (NFs). It was found that the CuO NFs have many p-p homojunctions and lots of chemisorbed oxygen, allowing for excellent gas sensing behaviors towards H 2 S at room temperature (RT). Interestingly, the ICCNs’ sensors favor to detect NH 3 gas. Amongst them, ICCN-5 (short for the sensor composite where the molar ratio of Cu: In is 100: 5) behaves very fast response, excellent selectivity and good stability (within 30 days) toward 10 ppm NH 3 at RT. The significantly enhanced sensing property of ICCNs to NH 3 could be attributed to the synergistic effect of In 2 O 3 promoter, multijunctions and unique mesoporous structure of NFs. Our studies demonstrated that 1D-CuO and ICCN-5 sensors were promising candidates of practical detectors to H 2 S and NH 3 at RT.