Stably dispersed metallophthalocyanine noncovalently bonded to multiwalled carbon nanotubes for ammonia sensing at room temperature

Herein, a series of tetra-α-isopentyloxyphthalocyanine copper, nickle, lead (CuPc-3, NiPc-3, PbPc-3) have been successfully bonded on the surface of acidified multi-walled carbon nanotubes (MWCNTs) by using a solution self-assembly method based on π-π stacking interaction facile reaction. The obtained MPc-3/MWCNTs (M = Cu, Ni, and Pb) hybrids display good dispersibility in DMF, which is beneficial to construct uniform sensing devices. The MPc-3/MWCNTs sensors exhibit excellent sensing performance, in terms of sensitivity, reversibility, reproducibility, selectivity and stability, especially CuPc-3/MWCNTs sensor in detail, the response is about 40.5% (80 ppm), the limit of detection is as low as 75 ppb, and the recovery time is about as fast as 180 s at room temperature. The enhanced NH3-sensing performance is mainly due to the synergistic effect between MPc-3 and MWCNTs, e.g. the stronger adsorption interaction of MPc-3 with NH3, the high electrical conductivity of MWCNTs, and the fast charge transfer between MPc-3 and MWCNTs. The systematic study developed here provides a valid way to fabricate high-efficient NH3 sensors.