tamald

• Kozdra, Sylwia; Wójcik, Adrianna; Das, Tamal & Michałowski, Paweł Piotr (2023). From DFT investigations of oxygen-implanted molybdenum disulfide to temperature-induced stabilization of MoS<inf>2</inf>/MoO<inf>3</inf> heterostructure. Applied Surface Science. ISSN 0169-4332. 631. doi: 10.1016/j.apsusc.2023.157547. Fulltekst i vitenarkiv Vis sammendrag

  In this work, we study the mechanism of the implantation process of two-dimensional molybdenum disulfide. We proposed the oxidation scheme and investigated the changes in the geometry of the MoS2 layer, as well as HOMO and LUMO orbitals location using the Density Functional Theory technique. We found that the oxygen was incorporated into the MoS2 structure and the MoS2/MoO3 heterostructure was created. The effect of implantation and the presence of heterostructure was investigated in the Secondary Ion Mass Spectrometry technique with atomic-resolution depth profiles. The presence of molybdenum trioxide was confirmed using Raman spectroscopy. The successful implantation allowed to obtain a stable conductive/insulating heterostructure of MoS2/MoO3 with promising properties.

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• Das, Tamal & Nova, Ainara (2022). The Multiple Configurations of μ3-OH Functionalized UiO-MOFs and its Potential Relevance in Catalysis. Fulltekst i vitenarkiv Vis sammendrag

  One strategy to incorporate metal catalysts (MX) into the Zr6O8 nodes of UiO-type metal organic frameworks (MOF) is by μ3-OH proton exchange. In this approach, the relative position of the μ3−OH or μ3−OMX (after functionalization) in the tetrahedral (Td) pore become very relevant since it defines the chemical environment of the reaction. In this work, DFT methods have been used to study the different configurations of UiO MOFs, denoted as [4,0], [3,1] and [2,2] depending on the number of μ3−OH or μ3−OMX pointing into the tetrahedral (Td) pores. Periodic gas phase  DFT calculations on UiO-66 and UiO-67 show that the [4,0] configuration is the most stable and [2,2] is the least stable for the functionalized μ3−OH sites with MX groups being M=Mg, Ca, or Zn, and X=Me, Cl and Br. Furthermore, ab initio molecular dynamics (AIMD) study reveals that node de-metalation occurs from the μ3−OMgMe sites of less stable conformers under explicit solvation (THF) suggesting that the relocation of the catalyst during a postsynthetic metalation is feasible. Calculations also showed a largest compression of the unit cell volume for the UiO-67 [4,0] configuration after metalation. These results should help to understand the reactivity of μ3-OMX single-site catalysts and exploit the potential of this type of functionalization.  

• Das, Tamal & Nova, Ainara (2022). The Multiple Configurations of μ3-OH Functionalized UiO-MOFs and its Potential Relevance in carbon capture and conversion. Fulltekst i vitenarkiv Vis sammendrag

  One strategy to incorporate metal catalysts (MX) into the Zr6O8 nodes of UiO-type metal organic frameworks (MOF) is by μ3-OH proton exchange. In this approach, the relative position of the μ3−OH or μ3−OMX (after functionalization) in the tetrahedral (Td) pore become very relevant since it defines the chemical environment of the reaction. In this work, DFT methods have been used to study the different configurations of UiO MOFs, denoted as [4,0], [3,1] and [2,2] depending on the number of μ3−OH or μ3−OMX pointing into the tetrahedral (Td) pores. Periodic gas phase  DFT calculations on UiO-66 and UiO-67 show that the [4,0] configuration is the most stable and [2,2] is the least stable for the functionalized μ3−OH sites with MX groups being M=Mg, Ca, or Zn, and X=Me, Cl and Br. Furthermore, ab initio molecular dynamics (AIMD) study reveals that node de-metalation occurs from the μ3−OMgMe sites of less stable conformers under explicit solvation (THF) suggesting that the relocation of the catalyst during a postsynthetic metalation is feasible. Calculations also showed a largest compression of the unit cell volume for the UiO-67 [4,0] configuration after metalation. These results should help to understand the reactivity of μ3-OMX single-site catalysts and exploit the potential of this type of functionalization.  

• Das, Tamal & Nova, Ainara (2022). Insight Into the Multiple Configurations of MOF based Single-Site Catalysts: Structure, Stability and Dynamics. Fulltekst i vitenarkiv Vis sammendrag

  One strategy to incorporate metal catalysts (MX) into the Zr6O8 nodes of UiO-type metal organic frameworks (MOF) is by μ3-OH proton exchange. In this approach, the relative position of the μ3−OH or μ3−OMX (after functionalization) in the tetrahedral (Td) pore become very relevant since it defines the chemical environment of the reaction. In this work, DFT methods have been used to study the different configurations of UiO MOFs, denoted as [4,0], [3,1] and [2,2] depending on the number of μ3−OH or μ3−OMX pointing into the tetrahedral (Td) pores. Periodic gas phase  DFT calculations on UiO-66 and UiO-67 show that the [4,0] configuration is the most stable and [2,2] is the least stable for the functionalized μ3−OH sites with MX groups being M=Mg, Ca, or Zn, and X=Me, Cl and Br. Furthermore, ab initio molecular dynamics (AIMD) study reveals that node de-metalation occurs from the μ3−OMgMe sites of less stable conformers under explicit solvation (THF) suggesting that the relocation of the catalyst during a postsynthetic metalation is feasible. Calculations also showed a largest compression of the unit cell volume for the UiO-67 [4,0] configuration after metalation. These results should help to understand the reactivity of μ3-OMX single-site catalysts and exploit the potential of this type of functionalization.  

• Das, Tamal & Nova, Ainara (2022). Insights Into Multi Configuration Single Metal-Site MOF Based Catalysts: Structure, Stability and Dynamics Study. Fulltekst i vitenarkiv Vis sammendrag

  One strategy to incorporate metal catalysts (MX) into the Zr6O8 nodes of UiO-type metal organic frameworks (MOF) is by μ3-OH proton exchange. In this approach, the relative position of the μ3−OH or μ3−OMX (after functionalization) in the tetrahedral (Td) pore become very relevant since it defines the chemical environment of the reaction. In this work, DFT methods have been used to study the different configurations of UiO MOFs, denoted as [4,0], [3,1] and [2,2] depending on the number of μ3−OH or μ3−OMX pointing into the tetrahedral (Td) pores. Periodic gas phase  DFT calculations on UiO-66 and UiO-67 show that the [4,0] configuration is the most stable and [2,2] is the least stable for the functionalized μ3−OH sites with MX groups being M=Mg, Ca, or Zn, and X=Me, Cl and Br. Furthermore, ab initio molecular dynamics (AIMD) study reveals that node de-metalation occurs from the μ3−OMgMe sites of less stable conformers under explicit solvation (THF) suggesting that the relocation of the catalyst during a postsynthetic metalation is feasible. Calculations also showed a largest compression of the unit cell volume for the UiO-67 [4,0] configuration after metalation. These results should help to understand the reactivity of μ3-OMX single-site catalysts and exploit the potential of this type of functionalization.  

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