MOF-derived bow-like Ga-doped Co3O4 hierarchical architectures for enhanced triethylamine sensing performance

Metal-organic frameworks (MOF)-derived semiconductor materials are widely employed in the field of gas sensor because of their unique structural advantages. In this work, hierarchical bow-like Ga-doped Co3O4 architectures assembled by ultrathin and porous nanosheets have been synthesized by the assistance of Co-MOFs. The obtained Ga-doped Co3O4 samples (the molar ratio of Ga/Co = 0, 1%, 2% and 5%) are analyzed using XRD, TEM, FESEM, XPS, BET and PL. The gas sensing performance of the samples is investigated systematically. The results show that 2 at% Ga-doped Co3O4 sensor possesses excellent sensing performance, which is far superior to that of pure Co3O4 sensor. Specifically, 2 at% Ga-doped Co3O4 sensor shows high responses (108) to 50 ppm triethylamine (TEA) at a low working temperature of 180 °C, which are about 30 times than that of pure Co3O4 (3.5). Furthermore, it exhibits rapid response/recovery speed (3 s/15 s), low detection limit (0.1 ppm), excellent selectivity, repeatability and long-term stability. The enhanced gas sensing mechanism and possible selectivity mechanism are discussed in detail.