Methylcyclopentane conversion over platinum single crystal surfaces: Evidence for the cyclic mechanism of n-hexane isomerization

Kinetics of deactivation of bifunctional Pt/Al2O3Cl catalysts by coking

“…This is evident from the benzene selectivity data given in Table 2, whi :h shows the benzene selectivity to be negligible for the case of the acid catalyst only. The metallic function provides the necessary dehydrogenation activity, while the acidic function is needed for ring expansion (Zaera, 1986;Weisz, 1962). The selectivity for benzene as a function of time is given in Figure 6 for the different catalysts.…”

Active sites and states in the heterogeneous catalysis of carbon–hydrogen bonds

“…Isomerization of n-hexane on Pt(111) to form 2-or 3-methylpentane at high pressures/temperatures is believed to occur via formation of a methylcyclopentane intermediate followed by its ring opening (Davis et al 1984;Zaera et al 1986;Davis 1999). It has been speculated that this reaction pathway should include metallacycles as a reactive intermediate (Zaera 1995;Davis 1999).…”

“…Heterogeneous catalysis of C-H bonds cyclization and dehydrocyclization (Davis et al 1984;Zaera et al 1986). The main products from isomerizations of n-hexane are 2-and 3-methylpentane.…”

Product Selectivity Controlled by Nanoporous Environments in Zeolite Crystals Enveloping Rhodium Nanoparticle Catalysts for CO2 Hydrogenation

“…Supported metal nanoparticle (NP) catalysts continue to draw the attention of catalysis scientists because of their widespread applications in energy conversion and environmental protection. − Nanoparticle sizes and morphologies are crucial to the catalyst performance in numerous processes, in part because they affect the structures of the NP surfaces and thereby their reactivities. − Improved catalysts have emerged from efforts to (i) synthesize ultrasmall metal NPs (nanoclusters) and even isolated single atoms, − (ii) prepare nanocrystallites with selected and unique facets, − and (iii) select the compositions and structures of the supports. − Thus, the focus has been on tuning the NPs and the metal oxide/hydroxide interfaces they reside on. , Significantly, recent results show that, in reactions with liquid-phase reactants, the local environment of the metal NPs strongly influences the catalyst performance, illustrated by a significant enhancement of catalytic properties resulting from adjusting the hydrophobicity of the support. , There is still much to be learned about how the local environment of a metal NP affects catalyst performance, in particular, for challenging high-temperature reactions of gas-phase reactants such as in CO 2 hydrogenation. There are, we posit, opportunities for new approaches to tuning the local environments of metal NPs, and we address one of them here.…”