Periodic mesoporous organosilicas (PMOs) with methane and ethane bridging groups were synthesized by the condensation of bis(triethoxysilyl)methane and bis(triethoxysilyl)ethane, respectively, in an ultrafast sonochemical method with a short reaction time of 30 min using a cationic template (1-hexadecyl)trimethylammonium bromide (HTABr). Subsequently, the template HTABr was extracted by another 30 min of sonication in an acetone/HCl mixture. The whole experimental process for the synthesis and extraction of the PMOs took about 1 h, which is much shorter than any other reported methods. Both the PMOs have very high surface areas of 1200-1390 m(2) g(-1) with a narrow pore size distribution of approximately 3 nm. This sonochemical method further extended for the synthesis of large pore (pore size of approximately 5 nm) methane and ethane bridged PMOs using a triblock copolymer Pluronic P123 as template. The methane and ethane bridged PMO materials thus obtained were characterized by small-angle X-ray scattering, transmission electron microscopy, nitrogen sorption, and solid-state NMR techniques.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/la902239m | DOI Listing |
J Chem Phys
January 2025
Fritz Haber Research Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
Complex organic molecules are widespread in different areas of the interstellar medium, including cold areas, such as molecular clouds, where chemical reactions occur in ice. Among the observed molecules are oxygen-bearing organic molecules, which are of high interest given their significant role in astrobiology. Despite the observed rich chemistry, the underlying molecular mechanisms responsible for molecular formation in such cold dilute areas are still not fully understood.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Hefei National Research Center for Physical Science at Microscale, University of Science and Technology of China, Hefei, 230026, China.
Photocatalytic oxidative coupling of methane (OCM) offers an appealing route for converting greenhouse gas into valuable C hydrocarbons. However, O as the most commonly used oxidant, tends to result in inevitable overoxidation and waste of methane feedstock. Herein, we first report a photocatalytic OCM using CO as a soft oxidant for CH production under mild conditions, where an efficient photocatalyst with unique interface sites is designed and constructed to facilitate CO adsorption and activation, while concurrently boosting CH dissociation.
View Article and Find Full Text PDFChemistry
December 2024
University of Copenhagen, Chemistry, Universitetsparken 5, Kemisk Institut, 2100, Copenhagen, DENMARK.
The atmospheric concentration of carbon dioxide (CO2) has fluctuated throughout Earth's history. However, the role of CO2 in prebiotic chemistry has predominantly been limitedly postulated as a C1 precursor, which can be reduced to carbon monoxide or methane mimicking the Wood-Ljungdahl pathway. Herein we present neglected roles of CO2 as an active promoter in accessing biologically important C3-builidng blocks such as lactate, via redox-economic reaction cycles from cyanide (C1) and acetaldehyde (C2).
View Article and Find Full Text PDFACS Earth Space Chem
December 2024
Thermal Protection Materials Branch, NASA Ames Research Center, Moffett Field, California 94035, United States.
Molecular dynamics simulations were performed to characterize reaction products, resulting from solar wind irradiation, namely, H, of methane and methane-water ices. In our approach, we used seven 0.829 keV H (total energy of 5.
View Article and Find Full Text PDFChemphyschem
December 2024
Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, 555 Moo 1 Pa Yup Nai, Wang Chan, Rayong, 21210, Thailand.
To date, preparing materials with highly dispersed metal nanoparticles without metal agglomeration on a solid support is challenging. This work presents an alternative approach for synthesizing NiCo species on hierarchical ZSM-5 materials derived from a ZSM-5@NiCoAl-LDHs composite. The designed material was prepared by the growth of a NiCo-layered double hydroxides (LDHs) precursor on the surface of hierarchical ZSM-5 nanosheets.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!