The electroreduction-free stripping analysis of copper (II) ions and the voltammetric detection of nonylphenol and tetracycline based on graphdiyne/carbon nanotubes

The heavy metal ions (HMI) and π-electronical pollutants are two main types of environmental water contaminants, thus designing a universal sensor for their detection is considerable important. Meanwhile, graphdiyne (GDY) as a star material exhibits many unique advantages, especially superior adsorption and self-reducing property to HMI as well as great affinity to π-electron targets. Herein, by low-cost utilizing carbon nanotubes (CNTs) as the template dedicated to improve the conductivity and dispersibility of GDY, a multifunctional nanohybrid GDY/CNTs was prepared and then revealed successfully as a universal electrochemical sensing material for the HMI and π-electronical pollutants by adopting three models: (a) based on the in-situ adsorption and self-reduction capabilities of GDY towards HMI, an innovative electroreduction-free stripping voltammetry (FSV) sensing strategy was proposed for HMI detection via adopting Cu²⁺ as a representative, which can effectively avoid the electroreduction process compared with the common anodic stripping voltammetry method; (b) by selecting nonylphenol (NP) and tetracycline (TC) as two representative targets, the sensing performances of GDY/CNTs for the π-electronical pollutants were also confirmed. After optimizing the related experimental parameters, the as-prepared GDY/CNTs exhibits superior analytical performances (the obtained detection limits for Cu²⁺, NP and TC are respectively 1.6 nM, 6.67 nM and 1.67 nM coupled with the linearities of 0.005-10.0 μM, 0.02-25.0 μM and 0.005-6.0 μM) owing to the synergistic advantages of GDY and CNTs. This work revealed the as-prepared GDY/CNTs nanohybrids can be utilized as a robust universal sensing material for HMI and pollutants consisting of π-electrons, and especially the proposed FSV sensing strategy is very promising, exhibiting great potential applications.