02293nas a2200181 4500008004100000245016000041210006900201260000800270300001400278490000700292520156700299100001901866700003101885700002401916700003301940700001801973856012001991 2017 eng d00aCerium-based metal-organic framework having inherent oxidase-like activity applicable for colorimetric sensing of biothiols and aerobic oxidation of thiols0 aCeriumbased metalorganic framework having inherent oxidaselike a cOCT a5915-59250 v193 aA cerium-basedmetal-organic framework (MOF; 1) with a UiO-66 (UiO: University of Oslo) framework topology was synthesized solvothermally by employing 3,4-dimethylthieno[2,3-b] thiophene-2,5-dicarboxylic acid as a ligand. The MOF was thoroughly characterized by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction, infrared spectroscopy, and thermogravimetric and N-2 sorption analyses. The activated material (1') retained its structural integrity in water, acetic acid and 1 M HCl solution. XPS investigation reveals the presence of both Ce(III) and Ce(IV) ions in 1. Owing to the presence of mixed-valence cerium ions, 1' was able to oxidize the chromogenic peroxidase substrate 3,3', 5,5'-tetramethylbenzidine (TMB) or 2,2'azinobis.3- ethylbenzothizoline-6-sulfonic acid) (AzBTS) in the absence of an external oxidizing agent. Thus, it showed inherent oxidase-like catalytic properties. Inspired by the excellent oxidase-mimicking activity of 1', a protocol was developed for the rapid colorimetric sensing of biothiols in NaAc buffer (0.2 M, pH = 4). The sensing ability of 1' towards cysteine was also demonstrated in human blood plasma. Furthermore, the redox-active cerium ions enabled 1' to exhibit excellent heterogeneous catalytic performance in aerobic oxidation catalysis of thiol compounds. The material is reusable (both as a sensor and as a catalyst), lowcost and highly stable, which renders it a promising candidate for the monitoring of biothiols in immunoassays and medical diagnosis as well as for industrial oxidation catalysis.1 aDalapati, Rana1 aSakthivel, Balasubramanian1 aGhosalya, Manoj, K.1 aDhakshinamoorthy, Amarajothi1 aBiswas, Shyam uhttps://library.ncl.res.in/content/cerium-based-metal-organic-framework-having-inherent-oxidase-activity-applicable04103nas a2200205 4500008004100000245012200041210006900163260000800232300001600240490000700256520332100263100002903584700001903613700002303632700002403655700002603679700003303705700003003738856012903768 2019 eng d00a Molybdenum carbide catalyst for the reduction of CO2 to CO: surface science aspects by NAPPES and catalysis studies 0 aMolybdenum carbide catalyst for the reduction of CO2 to CO surfa cAUG a12199-122090 v483 a

Carbon dioxide is a greenhouse gas, and needs to be converted into one of the useful feedstocks, such as carbon monoxide and methanol. We demonstrate the reduction of CO2 with H-2 as a reducing agent, via a reverse water gas shift (RWGS) reaction, by using a potential and low cost Mo2C catalyst. Mo2C was evaluated for CO2 hydrogenation at ambient pressure as a function of temperature, and CO2 : H-2 ratio at a gas hourly space velocity (GHSV) of 20 000 h(-1). It is demonstrated that the Mo2C catalyst with 1 : 3 ratio of CO2 : H-2 is highly active (58% CO2 conversion) and selective (62%) towards CO at 723 K at ambient pressure. Both properties (basicity and redox properties) and high catalytic activity observed with Mo2C around 700 K correlate well and indicate a strong synergy among them towards CO2 activation. X-ray diffraction and Raman analysis show that the Mo2C catalyst remains in the beta-Mo2C form before and after the reaction. The mechanistic aspects of the RWGS reaction were determined by near-ambient pressure X-ray photoelectron spectroscopy (NAPXPS) with in situ generated Mo2C from carburization of Mo-metal foil. NAPXPS measurements were carried out at near ambient pressure (0.1 mbar) and various temperatures. Throughout the reaction, no significant changes in the Mo2+ oxidation state (of Mo2C) were observed indicating that the catalyst is highly stable; C and O 1s spectral results indicate the oxycarbide species as an active intermediate for RWGS. A good correlation is observed between catalytic activity from atmospheric pressure reactors and the electronic structure details derived from NAPXPS results, which establishes the structure-activity correlation.

1 aReddy, Kasala, Prabhakar1 aDama, Srikanth1 aMhamane, Nitin, B.1 aGhosalya, Manoj, K.1 aRaja, Thirumalaiswamy1 aSatyanarayana, Chilukuri, V.1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/molybdenum-carbide-catalyst-reduction-co2-co-surface-science-aspects-nappes-and-catalysis