TY - JOUR
T1 - In situ total scattering experiments of nucleation and crystallisation of tantalum-based oxides
T2 - From highly dilute solutions via cluster formation to nanoparticles
AU - Onur Şahin, Ezgi
AU - Tüysüz, Harun
AU - Chan, Candace K.
AU - Moon, Gun Hee
AU - Dai, Yitao
AU - Schmidt, Wolfgang
AU - Lim, Joohyun
AU - Scheu, Christina
AU - Weidenthaler, Claudia
N1 - Funding Information:
E. O. S. acknowledges the International Max Planck Research School for Interface Controlled Materials for Energy Conversion (IMPRS-SurMat) for funding. H. T. acknowledges MAXNET Energy consortium of Max Planck Society for financial support. C. K. C. and J. L. would like to thank the Alexander von Humboldt Foundation for support of this work through Humboldt Research Fellowships. C. W. thanks the Max Planck Society for basic funding. We acknowledge Diamond Light Source (UK) (Dr Dean Keeble, I15-1, proposal EE16372-1), the European Synchrotron Radiation Facility (France) (Dr Carlotta Giacobbe and Dr Jonathan Wright, ID11, proposal MA-3621) and Deutsches Elektronen-Synchrotron (Germany) (Dr Martin Etter, Petra III, P02.1, proposal I-20190175) for beamtime. We would like to express our gratitude to Dr Hilke Petersen and Jan Ternieden (Max-Planck-Institut für Kohlenforschung) who helped us during our in situ heating experiments, and Dr Michael Badawi (University of Lorraine) for discussions. We thank the mechanical workshop of the Max-Planck-Institut für Kohlenforschung for the fabrication of the analysis cells. Open Access funding provided by the Max Planck Society
Publisher Copyright:
© 2021 The Royal Society of Chemistry.
PY - 2021/1/7
Y1 - 2021/1/7
N2 - The exact formation mechanism of tantalum oxides (and in general, metal/mixed metal oxides) from alkoxide precursors is still not fully understood, particularly when forming cluster-like or amorphous materials. The structural evolution of Ta-based oxides was studied in detail using X-ray total scattering experiments along with subsequent pair distribution function (PDF) analyses. Starting from a tantalum alkoxide precursor (Ta2(OEt)10), the formation of hydrolysed TaxOyHz clusters in highly diluted aqueous solution was analysed. From the PDF data, the connectivity and arrangement of TaxOy octahedra in the cluster could be deduced as well as the approximate size of the clusters (<1 nm). Construction of cluster models allowed for identification of common structural motifs in the TaxOyHz clusters, ruling out the formation of chain- or ring-like clusters. More likely, bulky clusters with a high number of corner-sharing octahedra are formed. After separation of the amorphous solid from the liquid, temperature-induced crystallisation processes were monitored via in situ total scattering experiments. Between room temperature and 600 °C, only small rearrangements of the amorphous structure are observed. At about 610 °C, amorphous TaxOyHz transforms directly into crystalline orthorhombic L-Ta2O5 without formation of any crystalline intermediate structures.
AB - The exact formation mechanism of tantalum oxides (and in general, metal/mixed metal oxides) from alkoxide precursors is still not fully understood, particularly when forming cluster-like or amorphous materials. The structural evolution of Ta-based oxides was studied in detail using X-ray total scattering experiments along with subsequent pair distribution function (PDF) analyses. Starting from a tantalum alkoxide precursor (Ta2(OEt)10), the formation of hydrolysed TaxOyHz clusters in highly diluted aqueous solution was analysed. From the PDF data, the connectivity and arrangement of TaxOy octahedra in the cluster could be deduced as well as the approximate size of the clusters (<1 nm). Construction of cluster models allowed for identification of common structural motifs in the TaxOyHz clusters, ruling out the formation of chain- or ring-like clusters. More likely, bulky clusters with a high number of corner-sharing octahedra are formed. After separation of the amorphous solid from the liquid, temperature-induced crystallisation processes were monitored via in situ total scattering experiments. Between room temperature and 600 °C, only small rearrangements of the amorphous structure are observed. At about 610 °C, amorphous TaxOyHz transforms directly into crystalline orthorhombic L-Ta2O5 without formation of any crystalline intermediate structures.
UR - http://www.scopus.com/inward/record.url?scp=85099236360&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85099236360&partnerID=8YFLogxK
U2 - 10.1039/d0nr07871a
DO - 10.1039/d0nr07871a
M3 - Article
C2 - 33325940
AN - SCOPUS:85099236360
SN - 2040-3364
VL - 13
SP - 150
EP - 162
JO - Nanoscale
JF - Nanoscale
IS - 1
ER -