A CuO-CeO2-TiO2 catalyst for selective catalytic reduction of NOx with NH3 (NH3-SCR) at low temperatures was prepared by a sol-gel method and characterized by X-ray diffraction, Brunner-Emmett-Teller surface area, ultraviolet-visible spectroscopy, H2 temperature-programmed reduction, scanning electron microscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The CuO-CeO2-TiO2 ternary oxide catalyst shows excellent NH3-SCR activity in a low-temperature range of 150-250 °C. Lewis acid sites generated from Cu(2+) are the main active sites for ammonia activation at low temperature, which is crucial for low temperature NH3-SCR activity. The introduction of ceria results in increased reducibility of CuO species and strong interactions between CuO particles with the matrix. The interactions between copper, cerium and titanium oxides lead to high dispersion of metal oxides with increased active oxygen and enhanced catalyst acidity. Homogeneously mixed metal oxides facilitate the "fast SCR" reaction among Cu(2+)-NO, nitrate (coordinated on cerium sites) and ammonia (on titanium sites) on the CuO-CeO2-TiO2 catalyst at low temperatures.
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http://dx.doi.org/10.1021/am5004969 | DOI Listing |
J Plant Physiol
January 2025
Department of Ecology, Faculty of Sciences, University of Málaga, Málaga, Spain.
Cold-temperate and Arctic hard bottom coastal ecosystems are dominated by kelp forests, which have a high biomass production and provide important ecosystem services, but are subject to change due to ocean warming. However, the photophysiological response to increasing temperature of ecologically relevant species, such as Laminaria digitata, might depend on the local thermal environment where the population has developed. Therefore, the effects of temperature on growth rate, biochemical composition, maximum quantum yield, photosynthetic quotient and carbon budget of young cultured sporophytes of Laminaria digitata from the Arctic at Spitsbergen (SPT; cultured at 4, 10 and 16 °C) and from the cold-temperate North Sea island of Helgoland (HLG; cultured at 10, 16 and 22 °C) were comparatively analyzed.
View Article and Find Full Text PDFNanotechnology
January 2025
Nanjing University of Posts and Telecommunications, Nanjing University of Posts and Telecommunications, Kuala Lumpur, Selangor, 50603, MALAYSIA.
Two-dimensional Transition Metal Dichalcogenides (2D TMDs) have garnered significant attention in the field of materials science due to their remarkable electronic and optoelectronic properties, including high carrier mobility and tunable band gaps. Despite the extensive research on various TMDs, there remains a notable gap in understanding the synthesis techniques and their implications for the practical application of monolayer tungsten disulfide (WS2) in optoelectronic devices. This gap is critical, as the successful integration of WS2 into commercial technologies hinges on the development of reliable synthesis methods that ensure high quality and uniformity of the material.
View Article and Find Full Text PDFJ Occup Environ Hyg
January 2025
Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada.
With mines extending deeper and rising surface temperatures, workers are exposed to hotter environments. This study aimed to characterize heat stress and strain in the Canadian mining industry and evaluate the utility of the Heat Strain Score Index (HSSI), combined with additional self-reported adverse health outcomes. An exploratory web-based survey was conducted among workers ( = 119) in the Canadian mining industry.
View Article and Find Full Text PDFPLoS One
January 2025
Chemical & Petroleum Engineering Department, United Arab Emirates University, Al Ain, United Arab Emirates.
Oil fields located in cold environments and deep-sea locations often face challenges with paraffin wax buildup in pipelines during long-distance crude oil transportation. Various strategies have been employed to address this issue, with chemical methods being the most effective and economical. However, traditional chemical inhibitors present problems due to their high toxicity and low biodegradability, leading to increased operational costs and environmental concerns.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2025
Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, TX 75080.
The highest sheet symmetry form of graphyne, with one triple bond between each neighboring hexagon in graphene, irreversibly transforms exothermically at ambient pressure and low temperatures into a nongraphitic, planar-sheet, zero-bandgap phase consisting of intrasheet-bonded sp carbons. The synthesis of this sp carbon phase is demonstrated, and other carbon phases are described for possible future synthesis from graphyne without breaking graphyne bonds. While measurements and theory indicate that the reacting graphyne becomes nonplanar because of sheet wrinkling produced by dimensional mismatch between reacted and nonreacted sheet regions, sheet planarity is regained when the reaction is complete.
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