Preparation And Gas Sensing Properties Of Metalophthalocyanine And Carbon Nanotube Hybrid Materials

The tetra-(3-iso-pentyloxy) metal phthalocyanine MPc(3-iso-PeO)₄(M=Cu, Pb, Ni)and tetra-(4-iso-pentyloxy) metal phthalocyanine MPc(4-iso-PeO)₄(M=Cu, Ni, Pb, Zn)were synthesized and characterized by element analysis, HNMR, FTIR,MALDI-TOF-MS. Spin-coating films of tetra-(3-iso-pentyloxy) metal phthalocyanineMPc(3-iso-PeO)₄(M=Cu, Pb, Ni), tetra-(4-iso-pentyloxy) metal phthalocyanineMPc(4-iso-PeO)₄(M=Cu, Ni, Pb, Zn), tetra-(tert-butyl)-5,10,15,20-tetraazaporphyrinMTAP(t-Bu)₄[M=Pda Coa Ni] and tetra-(tert-butyl)-phthalocyanine copper CuPc(t-Bu)₄were obtained and characterized by Uv-Visa FTIR and AFM. The gas sensing behaviorsof the films were investigated with respect to NH3and NO2at room temperature. Inaddition, the effects of center metal, substituent group, conjugate ring and filmmorphology on gas sensing properties were also discussed.Seven kinds of novel carbon nanotube (CNT)/metalophthalocyanine (MPc) hybridswere prepared by noncovalent hybridization and characterized by Uv-Visa FTIRaRamana XPSa TEM and SEM, which includes three single wall carbon nanotube(SWCNT) hybrids (SWCNT-COOH/CuPc(3-iso-PeO)₄aSWCNT-COOH/PbPc(4-iso-PeO)₄and SWCNT-COOH/CuTTMPPc) and four multiwall carbon nanotube (MWCNT) hybrids (MWCNT-COOH/CuPc(3-iso-PeO)₄aMWCNT-COOH/PbPc(3-iso-PeO)₄a MWCNT-COOH/NiPc(3-iso-PeO)₄andMWCNT-COOH/PbPc(4-iso-PeO)₄). The results revealed that the MPc derivatives hadbeen successfully anchored on the surface of CNT through π–π stacking, and the chargetransferring conjugates were formed.The resistance of SWCNT-COOH/MPc films is5times bigger than SWCNT-COOHfilm and reduces about eight orders of magnitude than MPc film, and the resistance ofMWCNT-COOH/MPc films is2times bigger than MWCNT-COOH films and reducesabout seven orders of magnitude than MPc films. The electrical conductivity of MPc isevidently improved by functionalized CNT. This suggests that the measured resistanceof hybrids films is dominated by the resistivity of the CNT films. The conductivity ofMPc derivatives is greatly improved, thus enhanced its practical application. Novel chemiresistive sensors based on CNT/MPc have been successfully developed,and the gas sensing properties of CNT/MPc gas sensors to NH3has been studied for thefirst time. The result indicated that the detection limit of SWCNT-COOH/CuTTMPPcaSWCNT-COOH/CuPc(3-iso-PeO)₄a SWCNT-COOH/PbPc(4-iso-Peo)₄andMWCNT-COOH/CuPc(3-iso-PeO)₄films to NH3are generally in the ppb concentrationrange. By comparison with the CNT, the response of the CNT/MPc hybrids increases50%, the recovery times of CNT/MPc hybrids are shortened3-5times. The synergeticbehavior between MPc and CNT allows an excellent sensitivity to NH3. We present theimportant application prospect of CNT/MPc in the nitrogen noxious gas sensing field.