MOF-derived polyhedral NiMoO4@NiO p-p heterostructure as an effective bridge for regulating carriers enhanced sensitivity and selectivity to trimethylamine

Metal organic framework (MOF) has been considered as an ideal precursor to prepare the metal oxide semiconductor (MOS) composites. Herein, the polyhedral NiMoO4 decorated NiO p-p heterostructures are prepared using the MOF as a self-sacrificing template with an annealing process. Compared with the pure NiO, the 5 wt% NiMoO4 decorated NiO based sensor exhibits improved gas performance. It shows not only high response values of 150 and fast response/recovery speed (20 s/16 s) to 50 ppm TEA at a relatively low operating temperature of 220 °C, but also outstanding selectivity and stability, which indicates that the as-prepared polyhedral NiMoO4 decorated NiO heterostructures can be used as a promising material to detect TEA effectively. The gas-sensing mechanism of high selectivity and response to TEA for the NiMoO4 decorated NiO based sensor is closely related to the catalytic synergistic promotion effect of the NiO and NiMoO4 composite materials, the large specific surface area, and electronic sensitization by forming the p-p type heterostructures. This work also provides a new solution for designing well defined p-p heterojunctions in gas-sensing applications.