A Multitechnique Study of Fluorinated Nanodiamonds for Low-Energy Neutron Physics Applications

Michael Herraiz,Marc Dubois,Valery V Nesvizhevsky,Michela Brunelli,Chiara Cavallari,Vittoria Pischedda,Silvana Radescu,Nicolas Batisse

doi:10.1021/acs.jpcc.0c03083

Abstract

Data of quasi-specular reflection of cold neutrons, prompt-γ neutron analysis, X-ray Raman scattering (XRS), and neutron pair distribution function (PDF) analysis with powder of detonation nanodiamonds are analyzed to collect their structural properties and chemical composition. Both as-synthesized and purified samples were studied using fluorination samples. Removal of both the sp2 amorphous carbon shell and the hydrogen atoms is evidenced respectively by the change of neutron-nuclei optical potentials of nanoparticles and the increase of their neutron reflectivity. Moreover, sp3 diamond cores of nanoparticles stay intact during the fluorination as revealed by similar scattering patterns, PDF, and XRS data. Quasi-specular reflection, PDF, and XRS data are complementary for the study of nanomaterials and in good agreement with conventional characterization techniques (infrared spectroscopy and solid-state NMR).

Highlights

Fine investigation of nanomaterials needs a combination of complementary characterization techniques in order to collect information at different scales concerning their structure and chemical composition
Sp3 diamond cores of nanoparticles stay intact during the fluorination as revealed by similar scattering patterns, Pair distribution function (PDF) and X-ray Raman scattering (XRS) data
Quasi-specular reflection, PDF and XRS data are complementary for the study of nanomaterials and in good agreement with conventional characterization techniques

Summary

Introduction

Fine investigation of nanomaterials needs a combination of complementary characterization techniques in order to collect information at different scales concerning their structure and chemical composition. As a matter of fact, nanodiamond powder combines high volume density of diamond, high coherent scattering length (bC = 6.65 fm), low neutron absorption (σabsC = 3.5 mb) and inelastic scattering cross-sections of C. Cross-sections of neutron scattering on NDs have been studied in detail[13,14]. These investigations compare, in particular, different techniques of producing NDs and measure temperature dependence of inelastic scattering cross-sections. The authors show virtual absence of low-energy excitations highly elastic neutron scattering and underline the importance of clustering or agglomeration of nanoparticles in powders for neutron diffusion and transport. Important efforts have been devoted for including the diffusion of slow neutrons in the DND powder to neutron transport simulations[15,16]

Methods

Results

Conclusion