Estudo das propriedades de defeitos e superfície do MSnO3 (M=Sr, Cd, Zn e Mn) através de simulação computacional

• Ano de defesa: 2021
• Autor(a) principal: Freitas, Sabrina Marques de
• Orientador(a): Rezende, Marcos Vinícius dos Santos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Física
• Palavras-chave em Português: Física; Estanatos; Simulação atomística; Programa GULP; Morfologia
• Palavras-chave em Inglês: Minimum Energy Techniques Applied to Dislocation, Interface, and Surface Energies (METADISE); Stannates; Atomistic simulation; GULP program; Morphology
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://ri.ufs.br/jspui/handle/riufs/14721

The stannates are promising photocatalysts and lithium battery anodes. To optimize MSnO3 (M=Cd, Sr, Mn and Zn) for visible light activities and better cyclic battery capacity, the effects of doping with various cations are investigated using classical computer simulation. The main issues related to intrinsic defects, incorporation of dopants and reduction properties in MSnO3 were investigated. Our simulation model shows good reproduction of the observed structure of MSnO3. The most favourable intrinsic defect is the antisítio defect for all structures. Particular attention is paid to electronic processes due to their importance in the practical applications of the material. Solution energy from a range of dopants with loads ranging from +2 to +5 were presented. Where, for the divalent dopants (R2+= Cu, Ni, Fe, Me and Mn) and tetravalent (R4+=Fe, Ti, Pt and Ru) the mechanisms with lower solution energy are isovalent. For trivalent dopants (R3+= Bi, Cr, Fe, Al, Er, Tb, Eu, Sm, La and Nd), trivalent transition metal dopants and Al3+ preferred the Sn sítio with oxygen avoidance compensation in SrSnO3 and ZnSnO3, respectively. The rare earth group in SrSnO3 is more energetically more supportive of the incorporation into Strontium's sítio. The results indicate that the pentavalent dopant (R 5+= V and Ta) at the Sn sítio are the most soluble dopants in SrSnO3 because they have negative solution energy. Both SrSnO3 and ZnSnO3 pentavalent dopants preferred the Sítio of Sn. It was observed that for most dopants there is a shortening of interatomic distances. A study on surface energy was carried out, allowing us to predict the morphology of SrSnO3 and pure CdSnO3.