Density functional investigation of reverse hydrogen spillover on zeolite supported Pd6 and Au6 clusters

• Published in: Catalysis today 2012-12, Vol.198 (1), p.110-115
• Main Authors: Deka, Ramesh Chandra, Baishya, Subhi
• Format: Article
• Language: English
• Subjects: Au6 and Pd6 clusters; Catalysis; catalytic activity; Chemistry; Density functional theory; energy; Exact sciences and technology; Faujasite zeolite; General and physical chemistry; hydrogen; Ion-exchange; metals; oxidation; Stepwise reverse hydrogen spillover; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; zeolites; Zeolites: preparations and properties
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2012.02.017

. [Display omitted] ► Stepwise reverse hydrogen spillover from faujasite to Pd6 and Au6 clusters. ► Hydrogenated Pd6 and Au6 clusters are more stable than the bare clusters. ► Two proton transfer is more favorable than one and three proton transfer. ► Oxidation of metal atoms with concomitant reduction of H+ to H−. The present density functional study investigates the stepwise reverse hydrogen spillover from bridging OH groups of the faujasite support to Pd6 and Au6 clusters. Calculations reveal that the process of proton transfer from the bridging OH groups results in hydrogenated clusters, M6Hn/FAU(3−n); M=Pd, Au and n=1–3, which are energetically preferable over faujasite supported bare clusters, M6/FAU(3H). The calculated reverse hydrogen spillover energy per transferred hydrogen atom for faujasite supported Pd6H3 and Au6H3 are −29.33kJmol−1 and −24.50kJmol−1, respectively. For both the metals, hydrogen migration results in partial oxidation of the metal atoms with concomitant reduction of H+ to H−.