Preparation and characterization of F-, O-, and N-containing carbon nanoparticles for pH sensing

Abstract

A novel sensing system was designed for pH measurements based on the enhanced and quenched photoluminescence (PL) and UV-Vis absorption of the diluted water solutions of F-, O-, and N-containing carbon nanoparticles (FON-CNPs). These FON-CNPs were solvothermally synthesized, dissolved, ultra-iltrated, and separated by thin-layer chromatography. The total luorine content in them was found to be 1.2-1.5 mmol per gram. Their TGA showed a total weight loss of 52.7% because of the thermal decomposition and detachment of the surface groups and the partial burning of the functionalized shell on the carbon core at temperatures below 1200 °C. TEM and Raman data conirmed the presence of graphitic structures in the carbon core. From the results of ATR FTIR and UV-Vis spectroscopies, we showed that a carbon shell incorporates diferent functional groups covering the carbon core. The surface groups of the carbon shell include carboxyl, phenolic, and carbonyl groups. Heterocyclic N-containing and amino groups and triluoromethyl groups supporting the hydrophobicity were also found. We suggested the possible reasons for the pH responses obtained with the sensing system considering them dependent on the de-protonation of functional groups with pH change.

Photo- and Radiofrequency-Induced Heating of Photoluminescent Colloidal Carbon Dots

“…The synthesis of O, N-CDs derived from the thermal processing of urea with citric acid precursors has been already previously reported in detail by our group [ 27 , 28 ]. Figure 1 a shows pictures of the O, N-CDs-based colloidal solutions under daylight and UV excitation.…”

Photoluminescent Recognition of Strong Alcoholic Beverages with Carbon Nanoparticles

“…1 H NMR spectrum was recorded at 400 MHz on a Varian Mercury 400 spectrometer with tetramethylsilane as an internal standard in DMSO- d 6 . Raman spectrum of carbon NPs was collected in the backscattered mode with a HORIBA Jobin Yvon-LabRAM ARAMIS integrated confocal micro-Raman system equipped with a microscope (BX41, Olympus, Japan) and a diode-pumped solid-state laser . A 633 nm laser was focused by an Olympus 100× objective lens (UPLSAPO, NA = 0.95) on the sample placed in an open-air environment at room temperature.…”

“…Raman spectrum of carbon NPs was collected in the backscattered mode with a HORIBA Jobin Yvon-LabRAM ARAMIS integrated confocal micro-Raman system equipped with a microscope (BX41, Olympus, Japan) and a diode-pumped solid-state laser. 53 A 633 nm laser was focused by an Olympus 100× objective lens (UPLSAPO, NA = 0.95) on the sample placed in an open-air environment at room temperature. The excited Raman scattering signal was collected by a Labram ARAMIS (Jobin-Yvon) spectrometer.…”

Preparation and Characterization of Carbon-Silicon Hybrid Nanostructures

“…Element mapping was carried out with an energy dispersive X-ray (EDX) spectrometer from Oxford Instruments. To study the nanohybrids, we also used a highresolution JEOL JEM-3000F TEM microscope with an accelerating voltage of 300 keV [21]. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imagining was done with a Jeol ARM200F (200 keV) FEG-TEM/STEM instrument.…”