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Broge NLN, Bertelsen AD, Nielsen IG, Kløve M, Roelsgaard M, Dippel AC, Jørgensen MRV, Iversen BB. Exploration of anion effects in solvothermal synthesis using in situ X-ray diffraction. Phys Chem Chem Phys 2024; 26:12121-12132. [PMID: 38587495 DOI: 10.1039/d4cp00541d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Solvothermal synthesis presents a facile and highly flexible approach to chemical processing and it is widely used for preparation of micro- and nanosized inorganic materials. The large number of synthesis parameters in combination with the richness of inorganic chemistry means that it is difficult to predict or design synthesis outcomes, and it is demanding to uncover the effect of different parameters due to the sealed and complex nature of solvothermal reactors along with the time demands related to reactor cleaning, sample purification, and characterization. This study explores the effect on formation of crystalline products of six common anions in solvothermal treatment of aqueous and ethanolic precursors. Three different cations are included in the study (Mn2+, Co2+, Cu2+) representing chemical affinities towards different regions of the periodic table with respect to the hard soft acid base (HSAB) classification and the Goldschmidt classification. They additionally belong to the commonly used 3d transition metals and display a suitable variety in solvothermal chemistry to highlight anion effects. The results of the solvothermal in situ experiments demonstrate a clear effect of the precursor anions, with respect to whether crystallization occurs or not and the characteristics of the formed phases. Additionally, some of the anions are shown to be redox active and to influence the formation temperature of certain phases which in turn relates to the observed average crystallite sizes.
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Affiliation(s)
- Nils Lau Nyborg Broge
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Andreas Dueholm Bertelsen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | | | - Magnus Kløve
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Martin Roelsgaard
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Ann-Christin Dippel
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Mads Ry Vogel Jørgensen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Bo Brummerstedt Iversen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
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Roelsgaard M, Kløve M, Christensen R, Bertelsen AD, Broge NLN, Kantor I, Sørensen DR, Dippel AC, Banerjee S, Zimmermann MV, Glaevecke P, Gutowski O, Jørgensen MRV, Iversen BB. A reactor for time-resolved X-ray studies of nucleation and growth during solvothermal synthesis. J Appl Crystallogr 2023; 56:581-588. [PMID: 37284256 PMCID: PMC10241040 DOI: 10.1107/s1600576723002339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 03/09/2023] [Indexed: 06/08/2023] Open
Abstract
Understanding the nucleation and growth mechanisms of nanocrystals under hydro- and solvothermal conditions is key to tailoring functional nanomaterials. High-energy and high-flux synchrotron radiation is ideal for characterization by powder X-ray diffraction and X-ray total scattering in real time. Different versions of batch-type cell reactors have been employed in this work, exploiting the robustness of polyimide-coated fused quartz tubes with an inner diameter of 0.7 mm, as they can withstand pressures up to 250 bar and temperatures up to 723 K for several hours. Reported here are recent developments of the in situ setups available for general users on the P21.1 beamline at PETRA III and the DanMAX beamline at MAX IV to study nucleation and growth phenomena in solvothermal synthesis. It is shown that data suitable for both reciprocal-space Rietveld refinement and direct-space pair distribution function refinement can be obtained on a timescale of 4 ms.
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Affiliation(s)
- Martin Roelsgaard
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Magnus Kløve
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Rasmus Christensen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Andreas D. Bertelsen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Nils L. N. Broge
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Innokenty Kantor
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
- Department of Physics, Technical University of Denmark, 2880 Kongens Lyngby, Denmark
| | - Daniel Risskov Sørensen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Ann-Christin Dippel
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Soham Banerjee
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | | | - Philipp Glaevecke
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Olof Gutowski
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Mads Ry Vogel Jørgensen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Bo Brummerstedt Iversen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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Mamakhel A, Gjørup FH, Kløve M, Borup K, Iversen BB. Synthesis of Phase-Pure Thermochromic VO 2 (M1). Inorg Chem 2022; 61:8760-8766. [PMID: 35649247 DOI: 10.1021/acs.inorgchem.2c00701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A highly reproducible, simple, and inexpensive synthesis method for obtaining phase-pure thermochromic monoclinic VO2 (M1) is presented. Vanadium(III) oxide and ammonium metavanadate were used as starting materials and no additional reducing agents are required. Heating a mixture of these two components under an argon atmosphere at 750 °C for 2-4 h provides the direct formation of VO2 (M1) without detectable impurity phases. The formation reaction of VO2 (M1) was studied using in situ powder X-ray diffraction (PXRD), where a pressed pellet of the precursor material was heated during the continuous collection of PXRD data on a two-dimensional detector. The formation takes place via at least two crystalline intermediate phases where the first forms at 170-185 °C (likely an ammonium and oxygen deficient (NH4)1-δVO3-δ phase), and the second at 230 °C (likely a more disordered phase due to the increased background intensity). We assume that the solid-state reaction between the unknown but likely disordered vanadate phase and vanadium(III) oxide starts at 395 °C in concert with the appearance of several other unknown crystalline phases. At 610-750 °C, phase-pure rutile VO2 (P42/mnm) is obtained, which upon cooling converts to monoclinic VO2 (M1). The product composition, microstructure, and homogeneity are characterized by Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The synthesized VO2 (M1) has a sharp reversible insulator-to-metal transition at 71.3 °C during heating and 59.5 °C during cooling, as characterized using differential scanning calorimetry, and resistivity and magnetic property measurements.
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Affiliation(s)
- Aref Mamakhel
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, Aarhus DK-8000, Denmark
| | - Frederik Holm Gjørup
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, Aarhus DK-8000, Denmark
| | - Magnus Kløve
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, Aarhus DK-8000, Denmark
| | - Kasper Borup
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, Aarhus DK-8000, Denmark
| | - Bo Brummerstedt Iversen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, Aarhus DK-8000, Denmark
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Ra M, Boo Y, Jeong JM, Batts-Etseg J, Jeong J, Lee W. Classification of crystal structures using electron diffraction patterns with a deep convolutional neural network. RSC Adv 2021; 11:38307-38315. [PMID: 35493237 PMCID: PMC9043913 DOI: 10.1039/d1ra07156d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/14/2021] [Indexed: 12/03/2022] Open
Abstract
Investigations have been made to explore the applicability of an off-the-shelf deep convolutional neural network (DCNN) architecture, residual neural network (ResNet), to the classification of the crystal structure of materials using electron diffraction patterns without prior knowledge of the material systems under consideration. The dataset required for training and validating the ResNet architectures was obtained by the computer simulation of the selected area electron diffraction (SAD) in transmission electron microscopy. Acceleration voltages, zone axes, and camera lengths were used as variables and crystal information format (CIF) files obtained from open crystal data repositories were used as inputs. The cubic crystal system was chosen as a model system and five space groups of 213, 221, 225, 227, and 229 in the cubic system were selected for the test and validation, based on the distinguishability of the SAD patterns. The simulated diffraction patterns were regrouped and labeled from the viewpoint of computer vision, i.e., the way how the neural network recognizes the two-dimensional representation of three-dimensional lattice structure of crystals, for improved training and classification efficiency. Comparison of the various ResNet architectures with varying number of layers demonstrated that the ResNet101 architecture could classify the space groups with the validation accuracy of 92.607%. The off-the-shelf deep convolutional neural network architecture, ResNet, could classify the space group of materials with cubic crystal structures with the prediction accuracy of 92.607%, using the selected area electron diffraction patterns.![]()
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Affiliation(s)
- Moonsoo Ra
- LightVision Inc., 20 Seongsuil-ro 12-gil, Seongdong-gu, Seoul 04793, Republic of Korea
| | - Younggun Boo
- LightVision Inc., 20 Seongsuil-ro 12-gil, Seongdong-gu, Seoul 04793, Republic of Korea
| | - Jae Min Jeong
- School of Materials Science and Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon-si, Gyeongsangnam-do 51140, Republic of Korea
| | - Jargalsaikhan Batts-Etseg
- School of Materials Science and Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon-si, Gyeongsangnam-do 51140, Republic of Korea
| | - Jinha Jeong
- LightVision Inc., 20 Seongsuil-ro 12-gil, Seongdong-gu, Seoul 04793, Republic of Korea
- TRIZ Center, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Woong Lee
- School of Materials Science and Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon-si, Gyeongsangnam-do 51140, Republic of Korea
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Broge NLN, Søndergaard-Pedersen F, Roelsgaard M, Hassing-Hansen X, Iversen BB. Mapping the redox chemistry of common solvents in solvothermal synthesis through in situ X-ray diffraction. NANOSCALE 2020; 12:8511-8518. [PMID: 32242591 DOI: 10.1039/d0nr01240h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solvothermal technology shows great promise in "green" materials synthesis, processing, and recycling. The outcome of a specific solvothermal reaction depends strongly on the solvent properties, and the versatility of solvothermal synthesis hinges on the very large changes in solvent properties as a function of temperature and pressure. Here, six simple 3d transition metal nitrate salts (Cu(ii), Ni(ii), Co(ii), Fe(iii), Mn(ii), Cr(iii)) were dissolved in five common solvents (water, ethanol, ethylene glycol, glycerol, and 10% hydrogen peroxide solution) and heated stepwise up to 450 °C at a pressure of 250 bar using an in situ reactor while X-ray scattering data was recorded. A range of crystalline phases were observed in the form of metallic phases, metal oxides, and other ionic compounds. These data by themselves provide simple recipes for synthesis of many technologically important 3d transition metal nanomaterials. However, more generally the oxidation states of the metals in the synthesized materials can be used to map the solvent redox properties under solvothermal conditions. It is found that glycerol and ethylene glycol are strongly reducing, ethanol is moderately reducing, while water is weakly oxidizing. The behavior of the hydrogen peroxide solution is more complex including both oxidization and reduction. Furthermore, it is observed that the reducing powers of ethanol, ethylene glycol, and glycerol are enhanced with increasing temperature. The mapping of the redox properties of these common solvents provides a method for tailoring a given reaction through choice of solvent and reaction temperature. Solvothermal processes represent an environmentally benign alternative to the use of toxic reducing agents in chemical reactions, and quantification of the redox chemistry is a first step in rational materials design.
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Affiliation(s)
- Nils Lau Nyborg Broge
- Center for Materials Crystallography, Department of Chemistry and iNano, Aarhus University, Denmark.
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