The present Highlight article shows the importance of the monitoring of bulk crystalline compounds for a more thorough understanding of heterogeneous catalysts at the intersection of catalysis, materials science, crystallography and inorganic chemistry. Although catalytic action is widely regarded as a purely surface-bound phenomenon, there is increasing evidence that bulk processes can detrimentally or beneficially influence the catalytic properties of various material classes. Such bulk processes include polymorphic transformations, formation of oxygen-deficient structures, transient phases and the formation of a metal-oxide composite. The monitoring of these processes and the subsequent establishment of structure-property relationships are most effective if carried out under real operation conditions. By focusing on synchrotron-based X-ray diffraction as the perfect tool to follow the evolution of crystalline species, we exemplify the strength of the concept with five examples from various areas of catalytic research. As catalyst activation studies are increasingly becoming a hot topic in heterogeneous catalysis, the (self-)activation of oxide- and intermetallic compound-based materials during methanol steam and methane dry reforming is highlighted. The perovskite LaNiO is selected as an example to show the complex structural dynamics before and during methane dry reforming, which is only revealed upon monitoring all intermediate crystalline species in the transformation from LaNiO into Ni/LaO/LaOCO. ZrO-based materials form the second group, indicating the decomposition of the intermetallic compound CuZr into an epitaxially stabilized Cu/tetragonal ZrO composite during methanol steam reforming, the stability of a ZrOC oxycarbide and the gas-phase dependence of the tetragonal-to-monoclinic ZrO polymorphic transformation. The latter is the key parameter to the catalytic understanding of ZrO and is only appreciated in full detail once it is possible to follow the individual steps of the transformation between the crystalline polymorphic structures. A selected example is devoted to how the monitoring of crystalline reactive carbon during methane dry reforming operation aids in the mechanistic understanding of a Ni/MnO catalyst. The most important aspect is the strict use of monitoring of the structural changes occurring during (self-)activation to establish meaningful structure-property relationships allowing conclusions beyond isolated surface chemical aspects.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8474056 | PMC |
http://dx.doi.org/10.1039/d1ce00817j | DOI Listing |
Environ Sci Technol
January 2025
Indian Institute of Technology-Delhi (IIT Delhi), Hauz Khas, New Delhi 110016, India.
Observation-based verification of regional/national methane (CH) emission trends is crucial for transparent monitoring and mitigation strategy planning. Although surface observations track the global and sub-hemispheric emission trends well, their sparse spatial coverage limits our ability to assess regional trends. Dense satellite observations complement surface observations, offering a valuable means to validate emission trends, especially in regions where emissions changes are substantial but debated.
View Article and Find Full Text PDFTrop Anim Health Prod
January 2025
Department of Animal and Fish Production, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria, 21545, Egypt.
Pomegranate peels are an industrial by-product high in sugar and phytochemical content and pose an environmental concern. Meanwhile, ensiling legume forage such as berseem is difficult due to its lower dry matter content and water-soluble carbohydrate-to-buffering capacity ratio, which leads to a poor fermentation process. To date, no studies have been conducted to investigate the effect of co-ensiling pomegranate peels with berseem.
View Article and Find Full Text PDFJ Dairy Sci
January 2025
Department of Applied Animal Science & Welfare, Swedish University of Agricultural Sciences (SLU), Box 7024, 753 23 Uppsala, Sweden.
Methane emissions from ruminant digestion contribute significantly to global anthropogenic greenhouse gas emissions. Members of the phylum Rhodophyta (red algae), particularly Asparagopsis sp., have shown promising results in reducing methane emissions in ruminants, due to their high content of halogenated methane analog compounds.
View Article and Find Full Text PDFAnimal
December 2024
School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom; Global Academy of Agriculture and Food Systems, University of Edinburgh, Edinburgh, United Kingdom.
Livestock directly contribute to greenhouse gas emissions, mainly through enteric fermentation and to a lesser extent manure management. Livestock feed composition plays a crucial role in diet quality and the resulting emissions from livestock. Diet composition varies seasonally particularly in tropical environments with long dry periods.
View Article and Find Full Text PDFFront Vet Sci
December 2024
College of Animal Science and Technology, Henan International Joint Laboratory of Nutrition Regulation and Ecological Raising of Domestic Animal, Henan Agricultural University, Zhengzhou, Henan, China.
Twenty-four cows were used in a randomized complete block design. Cows were assigned to three groups: (1) Control, (2) 3-nitrooxypropanol (NOP) of 200 mg/kg feed dry matter (10% NOP), and (3) NOP × MAL (10% NOP at 200 mg/kg feed dry matter plus 99% -malate at 10 g/kg feed dry matter). Cows were fed for 10-wk.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!