Detonation Nanodiamonds: A Comparison Study by Photoacoustic, Diffuse Reflectance, and Attenuated Total Reflection FTIR Spectroscopies.

Dmitry S Volkov,Petr K Krivoshein,Mikhail A Proskurnin

doi:10.3390/nano10122501

Abstract

The qualitative analysis of nanodiamonds by FTIR spectrometry as photoacoustic (FTIR–PAS), diffuse-reflectance (DRIFT), and attenuated total reflection (ATR) modalities was evaluated for rapid and nondestructive analysis and comparison of nanodiamonds. The reproducibility and signal-gathering depth of spectra was compared. The assignment of characteristic bands showed that only six groups of bands were present in spectra of all the modalities with appropriate sensitivity: 1760 (C=O stretch, isolated carboxyl groups); 1640–1632 (H–O–H bend, liquid water); 1400–1370 (non-carboxyl C–O–H in-plane bend and CH2 deformation); 1103 (non-carboxyl C–O stretch); 1060 (in-plane C–H bend, non-aromatic hydrocarbons and carbohydrates); 940 cm−1 (out-of-plane carboxyl C–O–H bend). DRIFT provides the maximum number of bands and is capable of measuring hydrogen-bonded bands and CHx groups. ATR provides the good sensitivity for water and C–H/C–C bands in the range 2000–400 cm−1. FTIR–PAS reveals less bands than DRIFT but more intense bands than ATR–FTIR and shows the maximum sensitivity for absorption bands that do not appear in ATR-IR spectra and are expedient for supporting either DRIFT or FTIR–PAS along with depth-profiling. Thus, all three modalities are required for the full characterization of nanodiamonds surface functional groups.

Highlights

Nanodiamonds (ND), due to the nanometer size of their primary particles, have a surface with a significant area and many functional groups [1,2]
The spectra of nanodiamonds for the studied brands are shown in Figures 1 and 2, and Figure A1 (Appendix A) for DRIFT, Figures 3 and 4, and Figure A2 for attenuated total reflection (ATR), and Figure 5 for FTIR–PAS
ATR is advantageous from the viewpoint of small sample amounts, DRIFT seems to be the best choice as it provides good sensitivity, especially with a high-sensitivity photovoltaic detector and, results in the maximum number of bands among all three modalities

Summary

Introduction

Nanodiamonds (ND), due to the nanometer size of their primary particles, have a surface with a significant area and many functional groups [1,2]. The initial charge goes through several stages of chemical treatment, mainly of an oxidizing nature This is necessary primarily for the removal of non-diamond forms of carbon. Auto Auto 10 kHz Room temperature DLaTGS or liquid nitrogen cooled photovoltaic MCT MIR KBr Diamond crystal with a lowered pressure screw with a flat end. Before recording the spectra with heating, the spectrum of an empty ATR crystal was recorded at 25 ◦C as a background, a small amount of the sample was placed on its surface, pressed with a screw, and a program of controlled heating was started at a rate of 0.25 ◦C/min from 25 ◦C to 215 ◦C, and spectra registration step every 2.5 ◦C.

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Discussion

Conclusion