A high performance sensor based on PANI/ZnTi-LDHs nanocomposite for trace NH3 detection

The organic/inorganic nanocomposites materials have obtained considerable interest in gas sensors field in virtue of synergetic or complementary effects between respective components. In this work, loose three-dimensional (3D) nanocomposite of polyaniline (PANI)/ZnTi layered double hydroxides (ZnTi-LDHs), capable of NH3 sensing with high response and great long-term stability at room temperature, was prepared by entrapping PANI into 3D hierarchical ZnTi-LDHs matrices. The hierarchical ZnTi-LDHs was synthesized by hydrothermal method, and the PANI was entrapped into the ZnTi-LDHs matrices uniformly via in-situ chemical oxidative polymerization. Comparative investigations on the NH3-sensing properties of the single component (PANI, ZnTi-LDHs) and composite of PANI/ZnTi-LDHs demonstrate that the as-prepared PANI/ZnTi-LDHs composite displays about 20 and 2 times enhancement in response value to 50 ppm NH3 at room temperature compared with the single PANI and ZnTi-LDHs, respectively. The composite sensor also exhibits good long-term stability and low limit of detection (200 ppb). Meanwhile, the unique 3D loose architecture of the composite contributes to unique dynamic characteristics of transient response and ultrafast recovery; the response time and recovery time measured are within 3s and 110s respectively. The underlying NH3-sensing mechanism for PANI/ZnTi-LDHs sensor, particularly the notable response enhancement was demonstrated.