TY - JOUR A1 - Karafiludis, Stephanos A1 - Ryll, T. W. A1 - Buzanich, Ana Guilherme A1 - Emmerling, Franziska A1 - Stawski, Tomasz Maciej T1 - Phase stability studies on transition metal phosphates aided by an automated synthesis T2 - Royal Society of Chemistry (RSC) N2 - Transition metal phosphates (TMPs) have attracted interest as materials for (electro-) catalysis, and electrochemistry due to their low-cost, stability, and tunability. In this work, an automated synthesis platform was used for the preparation of transition metal phosphate crystals to efficiently explore the multidimensional parameter space, determining the phase selection, crystal sizes, shapes. By using X-ray diffraction and spectroscopy-based methods and electron microscopy imaging, a complete characterization of the phase stability fields, phase transitions, and crystal morphology/sizes was achieved. In an automated three-reactant synthesis, the individual effect of each reactant species NH4+, M2+, and PO43- on the formation of transition metal phosphate phases: M-struvite NH4MPO4·6H2O, M-phosphate octahydrate M3(PO4)2·8H2O with M = Ni, Co and an amorphous phase, was investigated. The NH4+ concentration dictates the phase composition, morphology, and particle size in the Ni-system (crystalline Ni-struvite versus amorphous Ni-PO4 phase), whereas in the Co-system all reactant species - NH4+, Co2+, and PO43- - influence the reaction outcome equivalently (Co-struvite vs. Co-phosphate octahydrate). The coordination environment for all crystalline compounds and of the amorphous Ni-PO4 phase was resolved by X-ray absorption spectroscopy, revealing matching characteristics to its crystalline analogue, Ni3(PO4)2·8H2O. The automated synthesis turned out to be significantly advantageous for the exploration of phase diagrams due to its simple modularity, facile traceability, and enhanced reproducibility compared to a typical manual synthesis. PB - CrystEngComm CY - London KW - Automated synthesis KW - Phase diagrams KW - Transition metals KW - Phosphates KW - Local structure KW - Struvite PY - 2023 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/57915 AN - OPUS4-57915 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579151 VL - 25 IS - 30 SP - 4333 EP - 4344 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany