Synthesis, Characterization, and Application of Pt/PtO2-TiO2/SiO2 Materials on a Continuous Flow Packed Bed Microreactor for Enhanced Photocatalytic Activity under Sunlight

Autor(es)

Gusmao, Carolina de Araujo ; Borges, Laura Teixeira ; Palharim, Priscila Hasse ; Otubo, Larissa ; Rodrigues, Orlando ; Gouvea, Douglas ; Ramos, Bruno ; Silva Costa Teixeira, Antonio Carlos

• Tipo de documento: Artigo Científico
• Fonte: WATER; v. 14, n. 23, p. 18-pg., 2022-12-01.

Resumo

The present work aimed at the development of Pt-TiO2/SiO2 materials applied to the degradation of a pharmaceutical pollutant in a fixed-bed microreactor in continuous mode. First, a wide investigation of the optimal platinum content in TiO2/SiO2 was carried out based on extensive characterization through XRD, DRS, SEM, TEM, and XPS techniques. For the content range studied, no significant changes were observed in the crystallinity of the material, with peaks related to the anatase phase and PtO2 in the diffractograms. SEM images combined with EDS spectra indicated the presence of platinum and a large heterogeneity in the particles. MET analyses showed PtO2 nanoparticles in close contact with TiO2, allowing the formation of a type II heterojunction. XPS showed platinum in the 0 and +4 oxidation states, suggesting that platinum metal and PtO2 are both present. Regarding the degradation experiments, the optimal catalyst achieved 81% degradation of acetaminophen for a residence time of 1 h, while the catalyst without platinum reached only 27% degradation. The catalyst activity dropped from 81 to 57% in 2 h and remained stable for six reuse cycles. Increasing the inlet flow rate and concentration reduced the pollutant degradation although there was an increase in the reaction rate. Finally, a photocatalytic mechanism was proposed in which a type II heterojunction was developed, with generation of hydroxyl radicals by the positive holes in the VB of TiO2 as well as superoxide radicals by the electrons in the CB of PtO2. (AU)

• Processo FAPESP: 21/10919-8 - Projeto e fabricação de dispositivos microfluidicos para processamento térmico e eletroquímico de CO2
• Beneficiário: Bruno Ramos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 19/24158-9 - Destinação ambiental de poluentes emergentes em águas superficiais e alternativas sustentáveis de mitigação: abordagem híbrida experimental-computacional
• Beneficiário: Antonio Carlos Silva Costa Teixeira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 22/12331-0 - Síntese e caracterização de materiais Pt-TiO2/SiO2 e avaliação em reator fotocatalítico contínuo de leito fixo para degradação de fármacos
• Beneficiário: Laura Teixeira Borges
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica