Catalyst design from theory to practice: general discussion

Abstract

Hans-Joachim Freund opened the discussion of the paper by Alberto Roldan: How is the atomic hydrogen produced on the greigite surface? In the paper (DOI: 10.1039/C5FD00186B) there is no comment whether you studied dissociate hydrogen adsorption.Alberto Roldan answered: We agree with Prof. Freund that we have not studied the hydrogen dissociation on the surface. However, the experiments are carried out on small nanoparticles exposing different surfaces and edges where H 2 molecules dissociate, as DRIFTS tests (not published) have suggested by the formation of reduced carbonated species.Rutger van Santen remarked: According to Wachterhauser, the reactive phase is Mackinawite. This is a layered FeS phase. The S may also have a higher reactivity than that of Greigite. How does the activation of H 2 on Greigite compare with that of Mackinawite, and would the reactivity of S be such that SO groups form in the surface that helps to generate CO? The SO group can have a subsequent reaction with H 2 S to give S 2 , which would help to transform the Mackinawite to pyrite.

Local Fluxionality of Surface-Deposited Cluster Catalysts: The Case of Pt7 on Al2O3

“…On the other hand, after considerably longer time, the thermal equilibrium among all low-energy isomers will be achieved, which brings to question the reactivity on such clusters being considered at nearly fixed geometries (usually the global minimum). 32 An ensemble representation consisting of low energy isomers may be a better computational model for such occasions. 4,33 Finally, the computational tools that we have developed for this work could be useful for studying isomerization or fluxionality of other cluster catalysts.…”

“…These common binding sites will exist for a relatively long time when the system only fluctuates locally (namely, within the region) but not globally. On the other hand, after considerably longer time, the thermal equilibrium among all low-energy isomers will be achieved, which brings to question the reactivity on such clusters being considered at nearly fixed geometries (usually the global minimum) . An ensemble representation consisting of low energy isomers may be a better computational model for such occasions. , …”

Multilevel quantum mechanical calculations show the role of promoter molecules in the dehydration of methanol to dimethyl ether in H-ZSM-5

“…2. We use the hierarchical approach employed by Sauer et al 41–44,52,68–81 as shown in eqn (2): H Final = H PBE+D3 + Δ E MP2 + Δ E CCSD(T) .…”

“…2. We use the hierarchical approach employed by Sauer et al [41][42][43][44]52,[68][69][70][71][72][73][74][75][76][77][78][79][80][81] as shown in eqn (2):…”

Advances in Sustainable Catalysis: A Computational Perspective

“…Achieving all these goals will require the design of novel and efficient catalysts that are active under mild conditions and can be produced sustainably without leading to unacceptably high levels of toxic pollutants (Beletskaya and Kustov, 2010; Polshettiwar and Varma, 2010; Chua and Pumera, 2015; Egorova and Ananikov, 2016). However, before any of these new catalysts can be developed a fundamental understanding of the properties of the currently most efficient and environmentally sustainable options has to be obtained, in order to enable the design of their replacement (Campbell et al, 2016; Hutchings et al, 2016; Pelletier and Basset, 2016; Friend and Xu, 2017; Chen et al, 2018; Kornienko et al, 2018; Caddell Haatveit et al, 2019). Computational models have proved to be one of the most efficient and least resource heavy ways of obtaining such information and have now become an invaluable component in the field as a whole (Nørskov et al, 2009; Hansgen et al, 2010; Medford et al, 2015; Sutton and Vlachos, 2015; Greeley, 2016; Grajciar et al, 2018).…”