Thermo nicolet 380

Spectra were collected in Attenuated Total Reflection (ATR) mode, using a Thermo Nicolet 380 Fourier transform infrared spectrometer (Thermo Scientific TM, West Sacramento, CA, USA), with a Smart Orbit Diamond ATR accessory ((Thermo Scientific TM, West Sacramento, CA, USA). The FTIR spectra were recorded in the region between 4000–400 cm⁻¹, with 64 scans and a resolution of 2 cm⁻¹.

Size distribution was analyzed by dynamic light scattering (DLS) measurements and zeta potentials by Zetasizer Nano ZS (ZEN3600), Malvern (UK). The IR Fourier spectrometer Thermo NICOLET 380 (USA) confirmed the functionalization of CQDs via chelate claws or nitrogen fragments. Moreover, surface behaviour in water was completed by zeta potential measurements by Zetasizer Nano ZS (ZEN3600), Malvern (UK) again.
A summary of the optical effects due to the different CQDs’ core functionalizations was compared via the absorption spectrum from a spectrophotometer UV mini-1240 Shimadzu (Japan) in the 250–500 nm range. Massive fluorescence data was characterized by fluorescence intensity and stability in time from Agilent Technologies’ Cary Eclipse Fluorescence Spectrophotometer (USA).
The calculation for CQDs’metal sensing and the creation of the lineal prediction model in the Irving–Williams series were obtained using the OriginLab program and the machine learning method in Python 3.10, respectively.

The synthesized nanocomposites properties were characterized by X-ray diffraction (XRD, X’Pert PRO, PANalytical, The Netherlands) with Cu Kα radiation (λ = 0.15406 nm); Fourier transform infrared (FTIR) spectroscopy (Thermo-Nicolet-380, Thermo Fisher, Madison, WI, USA); photoluminescence (PL) spectroscopy, (Varian Cary Eclipse, CA, USA); UV–vis spectroscopy (2401 PC, Shimadzu, Kyoto, Japan); and scanning electron microscopy (SEM, Hitachi-S3000 H, Hitachi, Tokyo, Japan).