A step forward in metal nitride and carbide synthesis: from pure nanopowders to nanocomposites

Giordano, Cristina; Corbiere, Tristan

doi:10.1007/s00396-012-2865-x

Cited by 22 publications

(15 citation statements)

References 123 publications

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“…A variety of metal oxides when treated in flowing NH 3 , form oxynitrides, nitrides and metal . Transition metals are most easily reduced and/or nitrided . In previous studies, we used a fluidized bed approach to nitriding; transforming SiO 2 and cordierite to their oxynitrides …”

Section: Resultsmentioning

confidence: 99%

Chemical modification at and within nanopowders: Synthesis of core‐shell Al₂O₃@TiON nanopowders via nitriding nano‐(TiO₂)_0.43(Al₂O₃)_0.57 powders in NH₃

You

Sun

et al. 2017

J Am Ceram Soc

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Here, we demonstrate the potential utility of using chemical modification to reorganize metastable nanoparticles into nanostructured nanoparticles without coincidentally inducing extensive necking/sintering. The motivation for this effort derives from the concept that chemical reduction in a single component in a mixed-metal nanoparticle will create segregated islands of a second immiscible phase. Given the very high chemical energies inherent in nanoparticles, the formation of even smaller islands of a second phase can be anticipated to lead to extremely high interfacial energies that may drive these islands to diffuse to cores or surfaces to form core-shell structures that minimize such interfacial energies. Thus, ammonolysis of (TiO 2 ) 0.43 (Al 2 O 3 ) 0.57 composition nanopowders where both elements are approximately uniformly mixed at atomic length scales, under selected conditions (1000°C) for various periods of time at constant NH 3 flow rates leads primarily to the reduction in the Ti species to form TiN or TiON which then appears to diffuse to the surface of the particles. The final products consist of Al 2 O 3 @TiON core-shell nanopowders that remain mostly unaggregated pointing to a new mechanism for modifying nanopowder chemistries and physical properties. K E Y W O R D Score-shell, mixed metal oxide nanopowders, nanostructured nanopowders, nitridation, phase separation

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Section: Resultsmentioning

confidence: 99%

Chemical modification at and within nanopowders: Synthesis of core‐shell Al₂O₃@TiON nanopowders via nitriding nano‐(TiO₂)_0.43(Al₂O₃)_0.57 powders in NH₃

You

Sun

et al. 2017

J Am Ceram Soc

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“…Cu nanoparticles were synthesized by modification of a typical urea glass route methodology 45 . Copper(II) nitrate hydrate (CAS Number 13778-31-9, 99.999% trace metals basis) and urea (CAS 57-13-6, ACS, Reag.…”

Section: Synthesis Of Cu Nanoparticlesmentioning

confidence: 99%

“…The present contribution introduces an alternative, easy to use, and green (nontoxic) synthetic methodology for phase-pure, monodispersed Cu particles with different crystallinity. A sol-gel based procedure called urea glass route 45 was tailored for the first time for the preparation of pure copper particles.…”

Section: Introductionmentioning

confidence: 99%

Study on the structure vs activity of designed non-precious metal electrocatalysts for CO2 conversion

Rao

Yuan

Jeyachandran

et al. 2021

Preprint

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The rising level of carbon dioxide (CO2), mainly a consequence of human activities, it is leading to devastating consequences to our environment and has raised concerns to the public opinion. To face this issue, governments are working to reduce the level of CO2 emissions, whilst the scientific community is focusing to implement the electro-chemical conversion of the emitted CO2 (CO2RR) as source of added value chemicals. Due to the high stability of the CO2 molecule, to make its conversion practical, the process requires a suitable electro-catalyst. With the aim to understand the mechanism toward specific CO2RR product and thus increase selectivity, in this contribution, we have explored copper nanoparticles (Cu NPs), as one of the most promising catalyst for CO2 conversion, and investigated the reactivity as a function of selected experimental parameters. The results were rationalized via theoretical investigation, also discussed in the paper, to understand the mechanism behind their activity but, most importantly, to relate structure to selectivity. The Cu NPs, prepared via an unconventional sol-gel process, were shown to be pure, with homogeneous size and morphology, and were tested toward CO2RRs showing a total FE above 90%. The higher FE toward the production of C2H4 (up to 33% at an applied potential of -1.0 V) is one of the highest FE reported so far for Cu, without using expensive support. The final products were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

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“…However, commodity scale production is challenging given the required specialized and expensive apparatus and low production rates (generally < 100 nm/min). [37][38][39] Here, we report a simple reaction of AlCl 3 with hexamethyldisilazane [HMDS, (Me 3 Si) 2 NH] in tetrahydrofuran (THF) or acetonitrile (ACN) at 60 • C/N 2 to produce an AlN precursor, Al(NHSiMe 3 ) 3 (denoted as Al-HMDS for convenience), as suggested by reaction (3). The byproduct Me 3 SiCl (boiling point = 57 • C) can be removed easily along with THF/ACN and excess HMDS by drying at 80 • C/1 h/vacuum (vac).…”

Section: Introductionmentioning

confidence: 99%

Reactions of metal chlorides with hexamethyldisilazane: Novel precursors to aluminum nitride and beyond

Zhang

Indris

et al. 2021

J Am Ceram Soc.

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Metal nitrides are intensely investigated because they can offer high melting points, excellent corrosion resistance, high hardness, electronic and magnetic properties superior to the corresponding metals/metal oxides. Thus, they are used in diverse applications including refractory materials, semiconductors, electronic devices, and energy storage/conversion systems. Here, we present a simple, novel, scalable and general route to metal nitride precursors by reactions of metal chlorides with hexamethyldisilazane [HMDS, (Me 3 Si) 2 NH] in tetrahydrofuran or acetonitrile at low temperatures (ambient to 60 • C/N 2 ). Such reactions have received scant attention in the literature. The work reported here focuses primarily on the Al-HMDS precursor produced from the reaction of AlCl 3 with HMDS (mole ratio = 1:3) characterized by matrix-assisted laser desorption/ionization-time of flight, Fourier-transform infrared spectroscopy, thermogravimetric analysis-differential thermal analysis, and multinuclear nuclear magnetic resonance spectroscopy (NMRs) for chemical and structural analyses. The Al-HMDS precursor heated to 1600 • C/4 h/N 2 produces aluminum nitride, characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy/energy-dispersive Xray spectroscopy, and magic-angle spinning NMR. On heating to 800-1200 • C/4 h/N 2 , the precursor transforms to an amorphous, oxygen-sensitive powder with very high surface areas (>200 m 2 /g) indicating nanosized particles, which can be used as additives to polymer matrices to modify their thermal stabilities. Al 2 O 3 is also presented in the final product after heating, due to its high susceptibility to oxidation. This approach was extended via proof-of-concept studies to other metal chloride systems, including Zn-HMDS, Cu-HMDS, Fe-HMDS, and Bi-HMDS. The formed precursors are volatile, offering the potential utility as gas-phase deposition precursors for their corresponding metal nitrides.

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A step forward in metal nitride and carbide synthesis: from pure nanopowders to nanocomposites

Cited by 22 publications

References 123 publications

Chemical modification at and within nanopowders: Synthesis of core‐shell Al₂O₃@TiON nanopowders via nitriding nano‐(TiO₂)_0.43(Al₂O₃)_0.57 powders in NH₃

Chemical modification at and within nanopowders: Synthesis of core‐shell Al₂O₃@TiON nanopowders via nitriding nano‐(TiO₂)_0.43(Al₂O₃)_0.57 powders in NH₃

Study on the structure vs activity of designed non-precious metal electrocatalysts for CO2 conversion

Reactions of metal chlorides with hexamethyldisilazane: Novel precursors to aluminum nitride and beyond

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A step forward in metal nitride and carbide synthesis: from pure nanopowders to nanocomposites

Cited by 22 publications

References 123 publications

Chemical modification at and within nanopowders: Synthesis of core‐shell Al2O3@TiON nanopowders via nitriding nano‐(TiO2)0.43(Al2O3)0.57 powders in NH3

Chemical modification at and within nanopowders: Synthesis of core‐shell Al2O3@TiON nanopowders via nitriding nano‐(TiO2)0.43(Al2O3)0.57 powders in NH3

Study on the structure vs activity of designed non-precious metal electrocatalysts for CO2 conversion

Reactions of metal chlorides with hexamethyldisilazane: Novel precursors to aluminum nitride and beyond

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Chemical modification at and within nanopowders: Synthesis of core‐shell Al₂O₃@TiON nanopowders via nitriding nano‐(TiO₂)_0.43(Al₂O₃)_0.57 powders in NH₃

Chemical modification at and within nanopowders: Synthesis of core‐shell Al₂O₃@TiON nanopowders via nitriding nano‐(TiO₂)_0.43(Al₂O₃)_0.57 powders in NH₃