skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Role of CO 2 and Glycerol in the Formation of Urchin-Like Strontium Carbonate Particles
Green synthesis of micro/nanomaterials, using glycerol as a sustainable solvent, offers environmentally and health-friendly pathways. Glycerol’s versatility in a solvothermal synthesis is effective for nanoparticle production, yet its mechanistic role in carbonate material formation is unexplored. This study investigates urchin-like strontium carbonate formation via a glycerol-mediated solvothermal synthesis, employing in situ transmission electron microscopy (in situ TEM), scanning electron microscopy, density function theory (DFT), scanning transmission electron microscopy, and X-ray diffraction. In situ TEM observations unveil the initial stages of strontium hydroxide nucleation and subsequent growth as an intermediate phase. The findings suggested that the hyperbranched polymerization of glycerol plays a pivotal role in the formation of urchin-like morphology. Furthermore, the synergistic effect of glycerol and CO2 is proposed as the primary driver for the formation of strontium carbonate. Notably, observations showed a morphological transition from spherical to urchin-like with increasing reaction time. DFT studies proposed glycerol as a coadsorbent, boosting the adsorption energy of CO2 and directing its interaction with Sr(OH)2 resulting in the stable formation of SrCO3. This research provides valuable insights into the urchin-like strontium carbonate formation in a time-dependent process driven by the polymerization of glycerol and its high reactivity with dissolved CO2 at elevated temperatures.  more » « less
Award ID(s):
2311104 2334386
PAR ID:
10510614
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
ACS
Date Published:
Journal Name:
ACS Sustainable Chemistry & Engineering
Volume:
12
Issue:
8
ISSN:
2168-0485
Page Range / eLocation ID:
3185 to 3195
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; (, ACS Catalysis)
    Small nanoparticles of ceria deposited on a powder of CuO display a very high selectivity for the production of methanol via CO2 hydrogenation. CeO2/CuO catalysts with ceria loadings of 5%, 20%, and 50% were investigated. Among these, the system with 5% CeOx showed the best catalytic performance at temperatures between 200 and 350 °C. The evolution of this system under reaction conditions was studied using a combination of environmental transmission electron microscopy (E-TEM), in situ X-ray absorption spectroscopy (XAS), and time-resolved X-ray diffraction (TR-XRD). For 5% CeOx/Cu, the in situ studies pointed to a full conversion of CuO into metallic copper, with a complete transformation of Ce4+ into Ce3+. Images from E-TEM showed drastic changes in the morphology of the catalyst when it was exposed to H2, CO2, and CO2/H2 mixtures. Under a CO2/H2 feed, there was a redispersion of the ceria particles that was detected by E-TEM and in situ TR-XRD. These morphological changes were made possible by the inverse oxide/metal configuration and facilitate the binding and selective conversion of CO2 to methanol. 
    more » « less
  2. ; ; ; ; ; (, RSC Advances)
    null (Ed.)
    Sm-doped BiFeO 3 (Bi 0.85 Sm 0.15 FeO 3 , or BSFO) thin films were fabricated on (001) SrTiO 3 (STO) substrates by pulsed laser deposition (PLD) over a range of deposition temperatures (600 °C, 640 °C and 670 °C). Detailed analysis of their microstructure via X-ray diffraction (XRD) and transmission electron microscopy (TEM) shows the deposition temperature dependence of ferroelectric (FE) and antiferroelectric (AFE) phase formation in BSFO. The Sm dopants are clearly detected by high-resolution scanning transmission electron microscopy (HR-STEM) and prove effective in controlling the ferroelectric properties of BSFO. The BSFO ( T dep = 670 °C) presents larger remnant polarization (Pr) than the other two BSFO ( T dep = 600 °C, 640 °C) and pure BiFeO 3 (BFO) thin films. This study paves a simple way for enhancing the ferroelectric properties of BSFO via deposition temperature and further promoting BFO practical applications. 
    more » « less
  3. ; ; ; ; ; (, Small Methods)
    Abstract Electrocatalysis and photoelectrochemistry are critical to technologies like fuel cells, electrolysis, and solar fuels. Material stability and interfacial phenomena are central to the performance and long‐term viability of these technologies. Researchers need tools to uncover the fundamental processes occurring at the electrode/electrolyte interface. Numerous analytical instruments are well‐developed for material characterization, but many are ex situ techniques often performed under vacuum and without applied bias. Such measurements miss dynamic phenomena in the electrolyte under operational conditions. However, innovative advancements have allowed modification of these techniques for in situ characterization in liquid environments at electrochemically relevant conditions. This review explains some of the main in situ electrochemical characterization techniques, briefly explaining the principle of operation and highlighting key work in applying the method to investigate material stability and interfacial properties for electrocatalysts and photoelectrodes. Covered methods include spectroscopy (in situ UV–vis, ambient pressure X‐ray photoelectron spectroscopy (APXPS), and in situ Raman), mass spectrometry (on‐line inductively coupled plasma mass spectrometry (ICP‐MS) and differential electrochemical mass spectrometry (DEMS)), and microscopy (in situ transmission electron microscopy (TEM), electrochemical atomic force microscopy (EC‐AFM), electrochemical scanning tunneling microscopy (EC‐STM), and scanning electrochemical microscopy (SECM)). Each technique's capabilities and advantages/disadvantages are discussed and summarized for comparison. 
    more » « less
  4. ; ; ; ; ; ; ; (, Nanoscale)
    Ferritin is a protein that regulates the iron ions in humans by storing them in the form of iron oxides. Despite extensive efforts to understand the ferritin iron oxide structures, it is still not clear how ferritin proteins with a distinct light (L) and heavy (H) chain subunit ratio impact the biomineralization process. In situ graphene liquid cell-transmission electron microscopy (GLC-TEM) provides an indispensable platform to study the atomic structure of ferritin mineral cores in their native liquid environment. In this study, we report differences in the iron oxide formation in human spleen ferritins (HSFs) and human heart ferritins (HHFs) using in situ GLC-TEM. Scanning transmission electron microscopy (STEM) along with selected area electron diffraction (SAED) of the mineral core and electron energy loss spectroscopy (EELS) analyses enabled the visualization of morphologies, crystal structures and the chemistry of iron oxide cores in HSFs and HHFs. Our study revealed the presence of metastable ferrihydrite (5Fe 2 O 3 ·9H 2 O) as a dominant phase in hydrated HSFs and HHFs, while a stable hematite (α-Fe 2 O 3 ) phase predominated in non-hydrated HSFs and HHFs. In addition, a higher Fe 3+ /Fe 2+ ratio was found in HHFs in comparison with HSFs. This study provides new understanding on iron-oxide phases that exist in hydrated ferritin proteins from different human organs. Such new insights are needed to map ferritin biomineralization pathways and possible correlations with various iron-related disorders in humans. 
    more » « less
  5. ; ; ; (, PLOS ONE)
    Klymkowsky, Michael (Ed.)
    Canonical Wnt/β-catenin (cWnt) signaling is a crucial regulator of development and Dishevelled (Dsh/Dvl) functions as an integral part of this pathway by linking Wnt binding to the Frizzled:LRP5/6 receptor complex with β-catenin-stimulated gene expression. In many cell types Dsh has been localized to ill-defined cytoplasmic puncta, however in sea urchin eggs and embryos confocal fluorescence microscopy has shown that Dsh is localized to puncta present in a novel and development-essential vegetal cortex domain (VCD). In the present study, we used super-resolution light microscopy and platinum replica transmission electron microscopy (TEM) to provide the first views of the ultrastructural organization of Dsh within the sea urchin VCD. 3D structured illumination microscopy (SIM) imaging of isolated egg cortices demonstrated the graded distribution of Dsh in the VCD, whereas higher resolution stimulated emission depletion (STED) imaging revealed that some individual Dsh puncta consisted of more than one fluorescent source. Platinum replica immuno-TEM localization showed that Dsh puncta on the cytoplasmic face of the plasma membrane consisted of aggregates of pedestal-like structures each individually labeled with the C-terminus specific Dsh antibody. These aggregates were resistant to detergent extraction and treatment with drugs that disrupt actin filaments or inhibit myosin II contraction, and coexisted with the first cleavage actomyosin contractile ring. These results confirm and extend previous studies and reveal, for the first time in any cell type, the nanoscale organization of plasma membrane tethered Dsh. Our current working hypothesis is that these Dsh pedestals represent a prepositioned scaffold organization that is important for the localized activation of the cWnt pathway at the sea urchin vegetal pole. These observations in sea urchins may also be relevant to the submembranous Dsh puncta present in other eggs and embryos. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email