A Systematic Study on Bond Activation Energies of NO, N₂, and O₂ on Hexamers of Eight Transition Metals

Abstract

Catalytic bond activation pathways of diatomic molecules on small metal clusters have been studied by density functional theory calculations. The focus of this study is dissociation of NO, N2, and O2 on hexamers of eight transition metals (Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au). For all the 24 cases, the lowest energy structures at the molecular‐adsorption state, bond dissociation transition state (TS), and dissociative‐adsorption state were identified by a systematic procedure. At TS of 20 cases, the transition metal hexamer moiety took a different shape from bare transition metal hexamers. The results support the importance of metastable cluster structures in catalytic activity, recently proposed in several catalytic systems. Furthermore, using the obtained dataset, a simple linear regression analysis was made to explore the applicability of the Brønsted‐Evans‐Polanyi principle to flexible metal cluster catalysts.

Size-dependent reactivity of Rh cationic clusters to reduce NO by CO in the gas phase at high temperatures

“…A previous study on transition metal hexamer-assisted bond activation highlighted the importance of metastable cluster structures in assisting bond activation. 32 The active sites for NO dissociation and CO 2 formation were identified at the hollow site for n = 3 and the 4-fold hollow site for n = 6. In particular, the active sites for NO dissociation at n = 6 are similar to those on the Rh(100) surface.…”

“…The same procedure was used in our previous work on transition metal hexamer-assisted bond activation. 32 For small Rh clusters, the TPSSh functional provided accurate geometries and reaction energies with respect to the experimental results. 33 Therefore, the low-lying reactant, intermediate, product, and transition-state structures in the PBE results were further optimized at the TPSSh-D3/def2-SV(P) level of theory using the RI-J technique.…”

“…The same procedure was used in our previous work on transition metal hexamer-assisted bond activation. 32…”

Iterative multiscale and multi-physics computations for operando catalyst nanostructure elucidation and kinetic modeling

“…Thermodynamic correlations of adsorption energies of certain species, with a structurally related and simpler species, on similar adsorption site types across different materials are typically called adsorption scaling relations. 148 More useful are the linear correlations such as the Brønsted−Evans−Polanyi (BEP) relation that links the reaction energy for elementary steps (thermodynamics) with activation energy barriers (kinetics) 149 , 150 as accurate determination of transition state of reaction steps and thereby the activation energy barrier calculation by DFT is computationally more intensive than calculations of the intermediates. In this context, scaling relations are an attractive means for estimation of activation barriers for kinetic modeling of complex reaction networks.…”

Autonomous Reaction Network Exploration in Homogeneous and Heterogeneous Catalysis

“…They applied the SSW technique also for solids [201] and more complicated heterogeneous systems [202,203] by training a neural network on MD data, which is implemented in their LASP software package [204]. Besides surface slabs, also firstprinciples-based exploration methods have been applied to cluster models of nanoparticles based on graph rules by Habershon et al [205] and with the AFIR approach by Maeda et al [206][207][208].…”