Hierarchical NiGa2O4@C@CeO2 microstructure for sensitive and selective triethylamine gas sensing

Metal oxide heterostructures have been demonstrated excellent candidates acting as novel gas sensors with outstanding sensitivity and selectivity. In this work, a hierarchical NiGa2O4@C@CeO2 heterostructure with corn-like NiGa2O4 microcrystals covered by a thin carbon layer and then anchored with numerous amounts of external CeO2 nanoparticles was prepared through the combination of hydrothermal and a subsequent calcination method. The NiGa2O4@C@CeO2 composite demonstrates an excellent selective triethylamine (TEA) detection performance with a response of 11.1 towards 20 ppm TEA and a fast response/recovery time of 81 s/38 s. It also shows terrific selectivity for TEA when mixed with else interfering substances, along with prolonged reusability for at least 15 days. The enhanced TEA sensing performance can be ascribed to the significant improvement of conductivity and effective carrier transfer at the interface. This work provides a feasible method to fabricate metal oxide sensors with improved gas sensing performance.