Synthesis of Copper Nanocluster and Its Application in Pollutant Analysis

Abstract

Copper nanoclusters (Cu NCs) with their inherent optical and chemical advantages have gained increasing attention as a kind of novel material that possesses great potential, primarily in the use of contaminants sensing and bio-imaging. With a focus on environmental safety, this article comprehensively reviews the recent advances of Cu NCs in the application of various contaminants, including pesticide residues, heavy metal ions, sulfide ions and nitroaromatics. The common preparation methods and sensing mechanisms are summarized. The typical high-quality sensing probes based on Cu NCs towards various target contaminants are presented; additionally, the challenges and future perspectives in the development and application of Cu NCs in monitoring and analyzing environmental pollutants are discussed.

Keywords: environmental analysis; explosive; fluorescence; heavy metal; nanocluster; pesticide; pollutant; sensor; sulfide.

Scheme 1

Summary of ligands and templates for Cu NCs and their typical applications.

Figure 1

(a) Schematic representation of biosensor fabrication and suggested mechanism for paraoxon reduction; (b) (b1) The schematic illustration of ratiometric determination of dinotefuran based on S-CQDs/CuNCs probe; (b2) the emission spectra of S-CQDs and S-CQDs/CuNCs with and without the addition of DNF; (b3) selectivity analyses of as-developed ratiometric fluorescent probe mixed various interfering chemicals.

Figure 2

(a) Schematic illustration of Cu²⁺-quenched fluorescence turn-on assay for the detection of biothiols and AChE; (b) Schematic illustration of this ratio fluorescent sensing strategy for AChE activity sensing.

Figure 3

(a) Schematic Illustration of Hg²⁺ Quantification Based on Fluorescence Regulation of CuNCs via DNA Template Manipulation; (b) Schematic representation for the possible mechanism of Hg²⁺ and S²⁻ detection using TG-CuNCs.

Figure 4

(a) Schematic of apt-Cu@Au NCs aptasensor for Hg²⁺ ions detection; (b) (b1) Schematic of the preparation of CuNCs–CNQDs nanohybrid; (b2) Schematic for the Pb²⁺ detection assay.

Figure 5

(a) Schematic illustration of the preparation of GSH@CDs-Cu NCs and the application in the detection of Cr₂O₇²⁻ and Cd²⁺ ions; (b) Schematic illustration of the preparation of dual-emission ratiometric fluorescence probe and its sensing mechanism to Cu²⁺ ions.

Figure 6

(a) Schematic illustration of the preparation of MPA-Capped Cu NCs and the aggregation induced PL weakening of Cu²⁺@MPA-Cu NCs in the presence of S²⁻; (b) fluorescence emission spectra of Cu²⁺@MPA-Cu NCs in the presence of various concentrations of S²⁻ in Tris-HCl buffer solution; (c) effect of different anions on the fluorescence intensity of Cu²⁺@MPA-Cu NCs (red pillars), and the influence on the sensor in the presence of different anions coexisting with S²⁻ ions (green pillars).

Figure 7

(a) (a1) Schematic illustration of the synthesis of Cu NC/ZIF-8 composites from Zn²⁺ ions, 2 Mlm and Cu NCs; (a2) TEM images of Cu NC/ZIF-8 composites; (a3) PL (red, excited at 365 nm) and PLE (black, detection wavelength 600 nm) spectra of Cu NCs (dotted lines) and Cu NC/ZIF-8 composites (solid lines); (a4) the decrease in PL intensity of Cu NC/ZIF-8 composites to blank, toluene, NB, DNT, TNT, and the mixture of all above (concentration of all compounds 500 × 10⁻⁶ M); (a5) Linear relationship between the PL intensity of Cu NC/ZIF-8 composites and the concentration of TNT; (b) (b1) Schematic representation for the synthesis of GSH-CuNCs and its interaction with PM and followed by with PA; (b2) fluorescent spectral changes of GSH-CuNCs upon addition of various vitamin B6 cofactors; (b3) fluorescence spectral changes of PM-GSH-CuNCs in the presence of various nitro-aromatics; (b4) fluorescence spectral changes of PM-GSH-CuNCs upon addition of increasing [PA]; (b5) fluorescence color changes of the modified paper strips upon interaction with different concentrations of PA (1 mM to 10⁻⁷ M) observed under UV light at 365 nm.