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Ab initio study of the effects of ligands on the atomic structure, electronic stability and transition metal nanoclusters

Grant number: 13/15112-9
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): November 01, 2013
Effective date (End): July 31, 2017
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Juarez Lopes Ferreira da Silva
Grantee:Diêgo Guedes Sobrinho
Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
Associated research grant:08/00782-0 - Computational catalysis: hydrogen production from ethanol, AP.JP
Associated scholarship(s):14/22044-2 - (meta)stability of transition metal at finite temperature, BE.EP.DR

Abstract

The development of catalysts with high selectivity and low cost of production is a constant in chemistry, which has its importance for a large number of technology areas. In recent years, a great effort has been made to development catalysts for application in new renewable energy sources. For example, the production of H2 from ethanol towards the use of fossil fuels has been gaining attention in recent years due to the fact that ethanol is a renewable source. In this field of interest, several experimental studies have suggested the use of nanocatalyst composed of transition metal nanoclusters (TM), which can acquire a higher reactivity compared to macroscopic particles due to the possibility of manipulating the structural properties as a function of energy and chemical composition, shape and size of the nanoclusters. The current challenge is the synthesis and characterization of bimetallic nanocatalysts (TMnTMm - nanoalloys) efficient producers in terms of reactivity, conductivity and magnetism. Within this context, many studies have been devoted to the influence of molecular linkers to stabilization and control the size of nanoclusters in different chemical environments of synthesis and catalytic application. Recent experimental studies have indicated the possibility of structural characterization of nanoparticles with good resolution for larger dimensions than 3 nm. However, for nanoclusters of 1-3 nm still exists a difficulty in the current experimental methodology, impairing understanding of catalytic properties derived from information in the level atomic and electronic structure. A resource used in the synthesis of nanoclusters is the use of molecular linkers for control and stabilization size, however, some studies have shown a structural change caused by the addition of ligands on the surface of nanoclusters. Accordingly, for the better development of nanocatalysts with ligands, some questions remain open need a more effective, such as: (a) What the influence of ligands on the molecular atomic and electronic structures of nanoalloys? (B) What combinations between TMnTMm and ligands for the formation of more stable systems in the chemical environment? (C) Structural alterations of nanoalloys influence their catalytic efficiency with the addition of binders? (D) What is the influence of the solvent in these systems? A study using theoretical and computational methods can contribute to the resolution of these issues. In this PhD project, the student Diego Guedes Sobrinho will to study various combinations of these systems, as well as the catalytic properties of interest in each of them, using ab initio (density functional theory). (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
BESSE, RAFAEL; CATURELLO, NAIDEL A. M. S.; BASTOS, CARLOS M. O.; GUEDES-SOBRINHO, DIEGO; LIMA, MATHEUS P.; SIPAHI, GUILHERME M.; DA SILVA, JUAREZ L. F. Size-Induced Phase Evolution of MoSe2 Nanoflakes Revealed by Density Functional Theory. Journal of Physical Chemistry C, v. 122, n. 35, p. 20483-20488, SEP 6 2018. Web of Science Citations: 5.
GUEDES-SOBRINHO, DIEGO; CHAVES, ANDERSON S.; PIOTROWSKI, MAURICIO J.; DA SILVA, JUAREZ L. F. Density functional investigation of the adsorption effects of PH3 and SH2 on the structure stability of the Au-55 and Pt-55 nanoclusters. Journal of Chemical Physics, v. 146, n. 16 APR 28 2017. Web of Science Citations: 3.
PIOTROWSKI, MAURICIO J.; UNGUREANU, CRINA G.; TERESHCHUK, POLINA; BATISTA, KRYS E. A.; CHAVES, ANDERSON S.; GUEDES-SOBRINHO, DIEGO; DA SILVA, JUAREZ L. F. Theoretical Study of the Structural, Energetic, and Electronic Properties of 55-Atom Metal Nanoclusters: A DFT Investigation within van der Waals Corrections, Spin-Orbit Coupling, and PBE plus U of 42 Metal Systems. Journal of Physical Chemistry C, v. 120, n. 50, p. 28844-28856, DEC 22 2016. Web of Science Citations: 19.
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
SOBRINHO, Diêgo Guedes. Ab initio Study of the Ligands and Temperature Effects on the Stability and Meta-stability of Metallic Nanoclusters. 2017. Doctoral Thesis - Universidade de São Paulo (USP). Instituto de Química de São Carlos São Carlos.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.