Synthesis of Water-Soluble Cadmium Selenide/Zinc Sulfide Quantum Dots on Functionalized Multiwalled Carbon Nanotubes for Efficient Covalent Synergism in Determining Environmental Hazardous Phenolic Compounds

Increasing pollution and ecological imbalance have accentuated the need to develop sensors through an efficient technique. Typically, the core–shell nanocrystals of cadmium selenide/zinc sulfide (CdSe/ZnS) with functionalized multiwalled carbon nanotubes (f-MWCNTs) are used for developing an efficient electrochemical sensor that simultaneously detects 4-aminophenol (4-AP) and 4-nitrophenol (4-NP). The composite network formed by CdSe/ZnS quantum dots with the f-MWCNTs (CdSe/ZnS QDs @ f-MWCNT) behaves as an excellent electrocatalyst and provides a transportation pathway by engendering the electron–hole pair. The sensor exhibits low detection limit values of 34.8 and 17.7 nM for detection of 4-AP and 4-NP, respectively. The sensor also showed excellent sensitivity at a linear working range of 0.149–510 μM concentration for both the analytes. Additionally, the study also shows the potential for commercial feasibility of the as-prepared sensor by acquiring a satisfactory recovery percentage of the analytes in real-time biological and environmental sample analyses.