01990nas a2200217   4500008004100000022001400041245013800055210006900193260000800262490000800270520122900278653001201507653000801519653002301527653002501550653002501575653000801600100001801608700001801626856012801644       2024                        eng d  a0927-025600aWhat leads to direct epoxidation? an exhaustive DFT investigation of electrophilic oxygen mediated epoxidation of ethylene on Ag(100)0 aWhat leads to direct epoxidation an exhaustive DFT investigation  cAPR0 v2393 a<p>
	Extensive research has contributed to a better understanding of the commercially important epoxidation reaction. Selectivity, a crucial aspect of this reaction, has received significant attention in both experimental and theoretical investigations. However, a consensus regarding the role of electrophilic oxygen in epoxidation is yet to be reached. The present study is a theoretical examination of the prerequisites necessary for direct epoxidation to occur on the Ag(100) surface, at varied monolayer concentrations. Additionally, the study investigates the characteristics of various oxygen species interacting with ethylene to promote the direct epoxidation pathway. Based on the effective charges and projected density of states (pDOS) analysis, three oxygen variants were identified on the Ag(100) surface: atomic oxygen, dissociatively adsorbed molecular oxygen, and O 3 . The investigation reveals that all oxygen species, despite their physical and electronic differences, are electrophilic and undergo direct epoxidation. This work provides insights into the complex nature of epoxidation reaction and discusses electronic factors influencing the selective oxidation route on different Ag-O complexes.</p>
10aAg(100)10aDFT10aDirect epoxidation10aElectrophilic oxygen10aEthylene Oxide (EtO)10aOMC1 aNair, Aathira1 aJoshi, Kavita  uhttps://library.ncl.res.in/content/what-leads-direct-epoxidation-exhaustive-dft-investigation-electrophilic-oxygen-mediated02057nas a2200205   4500008004100000022001400041245008000055210006900135260000800204300001100212490000800223520141000231653001701641653001501658653002401673653000801697100001701705700001801722856011101740       2026                        eng d  a0169-433200aWhen facets meet impurities: Trace gas dominance over CO2 adsorption on ZnO0 aWhen facets meet impurities Trace gas dominance over CO2 adsorpt  cMAY  a1661510 v7293 a<p>
	The catalytic hydrogenation of CO2 to methanol using Cu-ZnO/Al2O3 (CZA) is a key route for sustainable chemical production, when coupled with CO2-rich industrial off-gases. However, trace secondary gases, though present only at ppm levels, can poison active sites and suppress catalytic performance. In this work, we employ periodic density functional theory (DFT) to investigate interactions of H2S, SO2, NO2, NO, CO and CH4 with ZnO surfaces:(10(-)10), (10(-)11), (11(-)20), (10(-)13), and (11(-)22), and compared their adsorption pattern with CO2, the principle component of methanol synthesis. H2S dissociates on all the surfaces, SO2, and NO2 are chemisorbed, CH4 remains physisorbed, and NO, CO, and CO2 exhibit facet-dependent adsorption. Electronic structure analysis reveal that chemisorption occurs when surface energy states near the Fermi level overlap with HOMO of adsorbate, enabling charge transfer, whereas physisorption lacks such overlap. The adsorption strength follows the order: H2S SO2 NO2 NO CO CO2 CH4, suggesting that sulfur and nitrogen containing species exhibit strong chemisorption and compete with CO2 for active sites, potentially impacting the efficiency of methanol synthesis. These insights provide an atomic scale understanding of impurity-surface interactions and highlight potential role of ZnO as an efficient feed stock purifier for CO2-rich gas streams.</p>
10aCZA catalyst10aflue gases10aValorization of CO210aZnO1 aBhati, Meema1 aJoshi, Kavita  uhttps://library.ncl.res.in/content/when-facets-meet-impurities-trace-gas-dominance-over-co2-adsorption-zno