ole of quantum-size effects in the dehydrogenation of CH4 on 3d TMn clusters: DFT calculations combined with data minin

Author(s)

Andriani, Karla F. ^[1] ; Felicio-Sousa, Priscilla ^[1] ; Morais, Felipe Orlando ^[2] ; Da Silva, Juarez L. F. ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, POB 400, BR-13566590 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: CATALYSIS SCIENCE & TECHNOLOGY; v. 12, n. 3 DEC 2021.
• Web of Science Citations: 0

Abstract

In this work, we report a theoretical investigation of the role of quantum-size effects (QSEs) in the dehydrogenation of methane (CH4) on 3d transition-metal clusters, TMn, where TM = Fe, Co, Ni, and Cu, and n = 4-15. Our calculations were based on density functional theory combined with the unity bond index-quadratic exponential potential (UBI-QEP) approach and data mining (Spearman rank correlation, clustering). We found via clustering techniques that QSEs or the chemical species, TMs, do not affect the adsorption modes (geometric orientation of the molecules) of CH4, CH3, CH3 + H, and H on the TMn clusters. However, QSEs play a crucial role in modulating the magnitude of the adsorption energy, reaction energy, dissociation energy, and activation energy, in particular, for Cu-n clusters due to the unpaired electron for clusters with an odd number of electrons. Through the UBI-QEP approach, we found small activation energy barriers for small Fe-n clusters and larger ones for Ni-n clusters, i.e., QSEs can be explored to tune energy barriers. These findings are supported by Spearman analysis; however, we could not identify a general trend due to the quantum-size effects that correlate activation energy with the adsorption and dissociation energies for the studied systems. (AU)

• FAPESP's process: 18/21401-7 - Multi-User Equipment approved in grant 2017/11631-2: cluster computational de alto desempenho - ENIAC
• Grantee: Juarez Lopes Ferreira da Silva
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 18/11152-0 - Catalyst design for direct conversion of methane to methanol: an ab initio Density Functional Theory investigation
• Grantee: Karla Furtado Andriani
• Support Opportunities: Scholarships in Brazil - Post-Doctoral