Publication Date:
2020
Description:
〈p〉Publication date: 5 June 2020〈/p〉
〈p〉〈b〉Source:〈/b〉 Applied Catalysis B: Environmental, Volume 266〈/p〉
〈p〉Author(s): Sonja Bekx-Schürmann, Sebastian Mangelsen, Philipp Breuninger, Hendrik Antoni, Ulrich Schürmann, Lorenz Kienle, Martin Muhler, Wolfgang Bensch, Wolfgang Grünert〈/p〉
〈h5〉Abstract〈/h5〉
〈div〉〈p〉Polycrystalline MoS〈sub〉2〈/sub〉 from (NH〈sub〉4〈/sub〉)〈sub〉2〈/sub〉MoS〈sub〉4〈/sub〉 thermolysis was activated in dilute H〈sub〉2〈/sub〉 at 523 K 〈 T〈sub〉R〈/sub〉 〈 873 K and studied by XRD, total scattering analysis, XPS, HRTEM, and chemisorption to explain, why coordinative unsaturation decreases with growing T〈sub〉R〈/sub〉 contrary to expectations from the MoS〈sub〉2〈/sub〉 structure. Hydrogenation rates were measured for identifying active sites. With increasing T〈sub〉R,〈/sub〉 activity and chemisorption peaked at different T〈sub〉R,peak〈/sub〉. Below T〈sub〉R,peak〈/sub〉, increasing activity was not paralleled by changes in MoS〈sub〉2〈/sub〉 microstructure. Decreasing chemisorption above T〈sub〉R,peak〈/sub〉 was assigned to saturation of vacancies by sulfide from internal defects and to inclusion of vacancies in the interior of aggregates. Upon high-temperature reduction, stacks grew anisotropically (basal planes extended), retaining defects like bending, turbostratic disorder. Preferential exposure of stack bases in aggregate surfaces resulted in enhanced decrease of chemisorption. Correlations between activity, edge area and (b)rim length estimated from a morphological model localized active sites in the (b)rim region.〈/p〉〈/div〉
〈h5〉Graphical abstract〈/h5〉
〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0926337320300382-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉
Print ISSN:
0926-3373
Electronic ISSN:
1873-3883
Topics:
Chemistry and Pharmacology
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