The effect of temperature on the vibrational properties of struvite crystals grown from silica gels was systematically studied by μ-Raman spectroscopy. The time-dependent Raman spectra recorded in the process of long time annealing of struvite crystal at 353 K do not indicate structural changes in the struvite crystal with the time of annealing. The temperature-dependent Raman spectra recorded in the range 298-423 K reveal a phase transition in struvite at about 368 K. Above this characteristic temperature, some of bands assigned to vibrations of the PO4 and NH4 tetrahedra and water molecules observed in the Raman spectra in low temperatures (orthorhombic phase) change their spectral parameters or disappear, which indicates a transition to a higher symmetry structure of struvite in the range of high temperatures.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.saa.2016.01.005 | DOI Listing |
Adv Mater
January 2025
State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China.
Copper-based electrocatalysts are recognized as crucial catalysts for CO electroreduction into multi-carbon products. However, achieving copper-based electrocatalysts with adjustable valences via one-step facile synthesis remains a challenge. In this study, Cu/CuO heterostructure is constructed by adjusting the anion species of the Cu ions-containing electrolyte during electrodeposition synthesis.
View Article and Find Full Text PDFFoods
January 2025
College of Food Science, Heilongjiang Bayi Agricultural University, Daqing 163319, China.
The feasibility of the two methodologies was confirmed to compare the results of determining mung bean origins using Raman and Near-Infrared (NIR) spectroscopy. Spectra from mung beans collected in Baicheng City, Jilin Province; Dorbod Mongol Autonomous, Tailai County, Heilongjiang Province; and Sishui County, Shandong Province, China, were analyzed. We established a traceability model using Principal Component Analysis combined with the K-nearest neighbor method to compare the efficacy of these methods in discriminating the origins of the mung beans.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Materials Science, Kaunas University of Technology, K. Baršausko 59, LT-51423 Kaunas, Lithuania.
This study explores the low-temperature synthesis of graphene using plasma-enhanced chemical vapor deposition (PECVD), emphasizing the optimization of process parameters to achieve controlled growth of pristine and hydrogenated graphene. Graphene films were synthesized at temperatures ranging from 700 °C to as low as 400 °C by varying methane (25-100 sccm) and hydrogen (25-100 sccm) gas flow rates under 10-20 mBar pressures. Raman spectroscopy revealed structural transitions: pristine graphene grown at 700 °C exhibited strong 2D peaks with an I(2D)/I(G) ratio > 2, while hydrogenated graphene synthesized at 500 °C showed increased defect density with an I(D)/I(G) ratio of ~1.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Institute of Materials Science, Kaunas University of Technology, K. Baršausko St. 59, LT-51423 Kaunas, Lithuania; Department of Physics, Kaunas University of Technology, Studentų St. 50, LT-51423 Kaunas, Lithuania. Electronic address:
Surface-enhanced Raman scattering (SERS) show great potential for rapid and highly sensitive detection of trace amounts of contamination from the environment in the surface aquatic ecosystem. The widespread use of antibiotics has resulted in serious degradation of the water environment in the past few years, and their substantial residual contamination of wastewater has a harmful effect on ecosystems, which is associated with the development of antibiotic-resistant bacterial strains. However, in this study, a novel approach of core-shell nanoparticles GNRs@1,4-BDT@Ag was used for the quantitative measurement of the concentration of antibiotics in wastewater solutions using the SERS technique coupled with computational methods.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
We study the Raman signature of stripe domains in monolayer WMoS alloys, characterized using experimental techniques and density functional theory (DFT) calculations. These stripe domains were found in star-shaped monolayer WS exhibiting a high concentration of molybdenum (Mo) atoms in its central region, and unique Raman peaks that were not previously reported. We attribute these peaks to the splitting of the original doubly degenerate E modes, arising from the lower symmetry of the W-Mo stripe domains.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!