p-Aminophenol sensor based on tetra-β-[3(dimethylamine) phenoxy] phthalocyanine cobalt(II)/multiwalled carbon nanotube hybrid

A highly efficient catalyst is a key challenge for developing electrochemical sensors for p-aminophenol (4-AP), which widely exists in the environment. In this paper, we describe a feasible synthesis for a tetra-beta-[3-(dimethylamine) phenoxy] phthalocyanine cobalt(II) (aPcCo) and acid-treated multiwalled carbon nanotube (CNT) hybrid using a strong pi-pi stacking interaction. The combination of aPcCo and CNT can improve the conductivity of aPcCo and the dispersion of CNT simultaneously, which benefits formation of uniform electrodes, and provides unimpeded pathways for matter diffusion, as well as accelerating charge-transfer kinetics. As a result, the aPcCo/CNT hybrid we produced can serve as an efficient electrochemical catalyst for 4-AP oxidation and provide more sensitive detection. The oxidation current of 4-AP is linear at concentrations from 0.5 mu M to 300 mu M and 300 mu M to 800 mu M. The detection limit is as low as 0.3 mu M (S/N = 3). This development offers an attractive catalyst material for electrochemical sensors.