Nanodiamonds obtained by the detonation method have been investigated by means of solid-state magnetic nuclear resonance (NMR) and electron paramagnetic resonance. 13C and 1H magic angle spinning (MAS) NMR and 13C MAS NMR with 1H to 13C cross-polarization allow the determination of surface-hydrogenated groups (CH, CH2, and COH) and the quasi-absence of an sp2 carbon fullerene-like shell on the diamond surface to be underlined. The 1H and 13C spin−lattice relaxation time (T 1) and second moment measurements are presented as a function of the temperature. Relaxation is shown to be mainly caused by paramagnetic centers in the case of 13C nuclei, whereas the presence of a molecular motion with an activation energy of 11.15 kJ·mol−1 is involved for 1H nuclei.

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Single-wall carbon nanotubes (SWCNTs) are fluorinated around 200 °C with molecular fluorine (F2) and xenon difluoride (XeF2) as fluorination agents. In this latter case, fluorination is carried out by atomic fluorine F• generated by the thermal decomposition of gaseous XeF2 on the nanotube surface. XeF2 treatment results in stoichiometries from CF0.05 to CF0.32, and F2 treatment gives compositions in the range CF0.04 and CF0.37. Transmission electronic microscopy (TEM), solid state Nuclear Magnetic Resonance (NMR), Raman scattering and Optical Absorption (AO) studies demonstrate that different fluorination mechanisms occur using molecular fluorine (F2) and atomic fluorine (F•). Atomic fluorine results in less sample damage and a more homogeneous fluorine distribution over the SWCNT surface than F2. This is explained via DFT calculations showing that HF catalyzed F2 deposition necessarily leads to highly fluorinated domain formation whereas F• addition occurs spontaneously at the initial species arrival site.

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This study describes the behavior of potential slow-release fertilizers (SRF), prepared by the mechanochemical activation of calcined Mg2Al-CO3 or Mg2Fe-CO3 layered double hydroxides (LDH) mixed with dipotassium hydrogen phosphate (K2HPO4). The effects of LDH thermal treatment on P/K release behavior were investigated. Characterizations of the inorganic composites before and after release experiments combined X-Ray diffraction (XRD), Fourier-transform infra-red spectroscopy (FTIR), solid-state nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The best release profile (<75% in 28 days and at least 75% release) was obtained for MgAl/K2HPO4 (9 h milling, 2:1 molar ratio, MR). Compared to readily used K2HPO4, milling orthophosphate into LDH matrices decreases its solubility and slows down its release, with 60% and 5.4% release after 168 h for MgAl/K2HPO4 and MgFe/K2HPO4 composites, respectively. Mechanochemical addition of carboxymethylcellulose to the LDH/K2HPO4 composites leads to a noticeable improvement of P release properties.

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A combination of original, powerful characterization techniques was used to make a thorough description of solid geopolymers and of the associated effect of varying the alkali cation sourceNaOH, KOH, or CsOHand aging for up to several years. More specifically, the local and pore structures were progressively determined from atomic local scale up to several nanometers by pair distribution function analysis (PDF), small-angle X-ray scattering (SAXS), and longer correlation concerning the pore network, and possible diffusion and accumulation phenomena were unraveled by thermoporosimetry and electrochemical impedance spectroscopy (EIS), respectively. These complementary observations resulted in a picture of an interface between the mineral and the porous network that was correlated to the solvated alkali cation present in the porous solution. After a short time of a few months, the Na-based geopolymer was found to exhibit a smooth interface built up from small "elementary" particles. This contrasted with the K-and Cs-based geopolymers, which presented developed interfaces arising from hierarchically organized smooth particles forming aggregates of fractal outer surface. This striking difference unraveled by SAXS and EIS is ascribed for the Na geopolymer to the contact of the solvated Na(H 2 O) x + cations with the amorphous mineral surface. The K(H 2 O) x + and Cs(H 2 O) x + solvated cations were an integral part of the porous solution, without direct contact with the mineral surface, thus leading to apparently rough interfaces. Dewatering occurred with time, mostly impacting the Na series. Overall, we obtained a detailed picture of the geopolymer series and their changes in time. The environment generated around the kosmotropic (ordermaking) Na + alkali cation was more prone to change upon aging toward a non-Debye type relaxation than the initially developed interface supplied by the chaotropic Cs + alkali cation, which was found to be relatively stable after 5 years. INTRODUCTIONGeopolymers are a class of largely X-ray amorphous threedimensional aluminosilicate binder materials, synthesized by the reaction of an aluminosilicate powder with a concentrated alkali metal silicate or hydroxide solution. 1 The geopolymerization mechanism is well described 2 and agreed upon, 3,4 proceeding with a dissolution−polycondensation that yields a gel of a three-dimensional network subsequently turning into a solid-state material through a structural reorganization of the binder. 5 The synthesis conditions, particularly the temperature, 5,6 and the reactants (aluminosilicate source and the nature and concentration of the alkali ions added to the activation solution) 6−9 are of prime importance for the

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