TY - JOUR
T1 - Towards a mechanistic understanding of the sol-gel syntheses of ternary carbides
AU - Siebert, Jan P.
AU - Juelsholt, Mikkel
AU - Günzing, Damian
AU - Wende, Heiko
AU - Ollefs, Katharina
AU - Birkel, Christina S.
N1 - Funding Information:
The authors acknowledge the use of facilities within the Eyring Materials Center at Arizona State University supported in part by NNCI-ECCS-1542160. DTA-MS data was gratefully received from Dr Martin Steinbrück and Ulrike Stegmaier at KIT, Germany. Financial support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project-ID 405553726—TRR 270 is acknowledged. We want to acknowledge the Diamond Light Source for beamtime on BL18, DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities and the Spallation Neutron Source, a department of Energy Office of Science User Facility operated by the Oak Ridge National Laboratory for providing neutron powder diffraction and total scattering measurements. Parts of this research were carried out at P02.1 and we would like to thank Alexander Schökel for assistance in using the beamline. We thank DANSCATT (supported by the Danish Agency for Science and Higher Education) for support. M. J. is grateful to the Villum Foundation for financial support through a Villum Young Investigator grant (VKR00015416). The authors also acknowledge Katharine Page for her guidance on the total scattering analyses.
Funding Information:
The authors acknowledge the use of facilities within the Eyring Materials Center at Arizona State University supported in part by NNCI-ECCS-1542160. DTA-MS data was gratefully received from Dr Martin Steinbr?ck and Ulrike Stegmaier at KIT, Germany. Financial support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)?Project-ID 405553726?TRR 270 is acknowledged. We want to acknowledge the Diamond Light Source for beamtime on BL18, DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities and the Spallation Neutron Source, a department of Energy Office of Science User Facility operated by the Oak Ridge National Laboratory for providing neutron powder diffraction and total scattering measurements. Parts of this research were carried out at P02.1 and we would like to thank Alexander Sch?kel for assistance in using the beamline. We thank DANSCATT (supported by the Danish Agency for Science and Higher Education) for support. M. J. is grateful to the Villum Foundation for financial support through a Villum Young Investigator grant (VKR00015416). The authors also acknowledge Katharine Page for her guidance on the total scattering analyses.
Publisher Copyright:
© 2022 The Royal Society of Chemistry
PY - 2022/2/18
Y1 - 2022/2/18
N2 - Sol-gel chemistry, while being extremely established, is to this day not fully understood, and much of the underlying chemistry and mechanisms are yet to be unraveled. Here, we elaborate on the sol-gel chemistry of Cr2GaC, the first layered ternary carbide belonging to the MAX phase family to ever be synthesized using this wet chemical approach. Leveraging a variety of both in- and ex situ characterization techniques, including X-ray and neutron powder diffraction, X-ray absorption fine structure analyses, total scattering analyses, and differential scanning calorimetry coupled with mass spectrometry, in-depth analyses of the local structures and reaction pathways are elucidated. While the metals first form tetrahedrally and octahedrally coordinated oxidic structures, that subsequently grow and crystallize into oxides, the carbon source citric acid sits on a separate reaction pathway, that does not merge with the metals until the very end. In fact, after decomposing it remains nanostructured and disordered graphite until the temperature allows for the reduction of the metal oxides into the layered carbide. Based on this, we hypothesize that the method is mostly applicable to systems where the needed metals are reducible by graphite around the formation temperature of the target phase.
AB - Sol-gel chemistry, while being extremely established, is to this day not fully understood, and much of the underlying chemistry and mechanisms are yet to be unraveled. Here, we elaborate on the sol-gel chemistry of Cr2GaC, the first layered ternary carbide belonging to the MAX phase family to ever be synthesized using this wet chemical approach. Leveraging a variety of both in- and ex situ characterization techniques, including X-ray and neutron powder diffraction, X-ray absorption fine structure analyses, total scattering analyses, and differential scanning calorimetry coupled with mass spectrometry, in-depth analyses of the local structures and reaction pathways are elucidated. While the metals first form tetrahedrally and octahedrally coordinated oxidic structures, that subsequently grow and crystallize into oxides, the carbon source citric acid sits on a separate reaction pathway, that does not merge with the metals until the very end. In fact, after decomposing it remains nanostructured and disordered graphite until the temperature allows for the reduction of the metal oxides into the layered carbide. Based on this, we hypothesize that the method is mostly applicable to systems where the needed metals are reducible by graphite around the formation temperature of the target phase.
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U2 - 10.1039/d2qi00053a
DO - 10.1039/d2qi00053a
M3 - Article
AN - SCOPUS:85127003013
SN - 2052-1545
VL - 9
SP - 1565
EP - 1574
JO - Inorganic Chemistry Frontiers
JF - Inorganic Chemistry Frontiers
IS - 7
ER -