Binder-Free ZnTPP/CNT Paper for Room Temperature Ammonia Sensor and Mechanism Investigation

Carbon nanotube (CNT) shows great potential in ammonia detection, but the drawback of low selectivity and poor sensitivity has persisted. Here, zinc-tetra (4-sulphonatophenyl) porphyrin (ZnTPP) is employed as a sensitizer, and the binder-free ZnTPP/CNT paper is obtained via a wet-papermaking technology and hot-pressing process. In the compound, ZnTPP anchored firmly on the CNT by means of the H-bonding and/or
$\pi $
-
$\pi $
conjugation, paper fibers and CNT/ZnTPP are served as the framework and “slurry,” respectively, generating the binder-free 3-D structure. Benefiting from the charge transfer process by the “interchange” of ZnTPP, the optimal ZnTPP/CNT paper (ZCP-2) indicates an outstanding selective, excellent stability, and good cycling response (162 and 531 s in response and recovery time) to NH
₃
. This work paves a new strategy for the improvement of the CNT-based material, which is meaningful for the field of ammonia sensors used in concentration calibration.