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Crystallisation of transition metal phosphate as precursors for mesoporous materials

  • The influence of several precipitation parameters on the crystal morphology and size of transition metal struvite is poorly investigated. We reveal the effect of different reaction conditions on the crystal shape and crystallite size of M-struvites (NH4MPO4∙6H2O, M = Mg2+, Ni2+, Co2+). Furthermore, we characterize the coordination environment of the crystalline end products and their related phases [Co-dittmarite (COD) NH4CoPO4∙H2O and Co(II)phosphate octahydrate (CPO) Co3(PO4)2∙8H2O]. Mg- and Ni-struvite are stable in multiple concentrations of the educts and metal/phosphorus (M/P) ratios in contrast to Co-struvite which forms below M/P ratios of 0.4. A high M/P ratio with high concentrations of the educts decrease the crystallite size and idiomorphism of the crystals while low M/P ratios with low concentrations of the educts increase the crystallite size and the euhedral formation of the crystal planes. In the (Ni, Co)-solid solutions Ni and Co are homogenously distributed in theThe influence of several precipitation parameters on the crystal morphology and size of transition metal struvite is poorly investigated. We reveal the effect of different reaction conditions on the crystal shape and crystallite size of M-struvites (NH4MPO4∙6H2O, M = Mg2+, Ni2+, Co2+). Furthermore, we characterize the coordination environment of the crystalline end products and their related phases [Co-dittmarite (COD) NH4CoPO4∙H2O and Co(II)phosphate octahydrate (CPO) Co3(PO4)2∙8H2O]. Mg- and Ni-struvite are stable in multiple concentrations of the educts and metal/phosphorus (M/P) ratios in contrast to Co-struvite which forms below M/P ratios of 0.4. A high M/P ratio with high concentrations of the educts decrease the crystallite size and idiomorphism of the crystals while low M/P ratios with low concentrations of the educts increase the crystallite size and the euhedral formation of the crystal planes. In the (Ni, Co)-solid solutions Ni and Co are homogenously distributed in the crystals with similar Ni# as in the aqueous solutions indicating no elemental fractionation in crystallization. Ni and Co-struvite exhibit a more centrosymmetric coordination environment compared to their related phases of COD and CPO determined by EXAFS. The CoO6 octahedron expands slightly the ideal size of the struvite structure and decomposes to Co-dittmarite. It is suggested that the crystallization of Ni- and Co-struvites follow a non-classical crystallization theory which consists of multiple nanophases on the way to the final crystal.zeige mehrzeige weniger

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Metadaten
Autor*innen:Stephanos KarafiludisORCiD
Koautor*innen:Tomasz Stawski, Ana de Oliveira Guilherme Buzanich, Franziska Emmerling
Dokumenttyp:Posterpräsentation
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2021
Organisationseinheit der BAM:6 Materialchemie
6 Materialchemie / 6.3 Strukturanalytik
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:Crystal Engineering; Mesoporosity; Nucleation
Themenfelder/Aktivitätsfelder der BAM:Chemie und Prozesstechnik
Veranstaltung:SALSA Make and Measure... and Machines
Veranstaltungsort:Online meeting
Beginndatum der Veranstaltung:16.09.2021
Enddatum der Veranstaltung:18.09.2021
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:06.10.2021
Referierte Publikation:Nein
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