ZIF-8-derived ZnTi-LDHs with unique self-supported architecture and corresponding LDHs/rGO hybrid for gas sensor applications

Abstract Layered double hydroxides (LDHs) have a great prospect in the gas sensor field owing to its unique layered structure, high porosity and large specific surface area. However, the poor conductivity and serious stacking of LDH layers have limited its application in rarefied gas detection. Focusing on the limitation, we have designed and constructed a hybrid of ZnTi-LDHs/rGO with hexahedral ZIF-8 oriented grown on GO as precursor and self-sacrificial templates. In the as-prepared LDHs/rGO hybrid, the derived ZnTi-LDHs well inherits the cage-shaped geometry of the ZIF-8 templates. Resultantly, the LDHs/rGO hybrid shows a unique architecture characterized by self-supported nanocages of LDHs dispersed on highly conductive rGO. The unique hybrid architecture, as well as the conductivity and heterojunction modulation introduced by rGO promotes the sensing responses and dynamic characteristic of LDHs-based sensor. The achieved sensor of ZnTi-LDHs/rGO nanohybrid is revealed to be sensitive to rarefied NO2 as low as 50 ppb at room temperature and shows gas response with 9-fold enhancement compared with the general ZnTi-LDHs sensor. Meanwhile, the hybrid sensor presents an excellent dynamic performance with fast response/recovery. The response enhancement of the LDHs/rGO hybrid is demonstrated in details.