Synergy between NiWO4 and chitosan for the development of catalysts for sulfide oxidation

Autor(es)

Grasser, Giovanna A. ; Ribeiro, Lara K. ; Longo, Elson ; Assis, Marcelo

• Tipo de documento: Artigo Científico
• Fonte: CATALYSIS TODAY; v. 444, p. 12-pg., 2025-01-15.

Resumo

In this work, catalysts based on composite films composed by chitosan with disordered NiWO4 (10, 20, and 40 % w/w) were synthesized for their application in the oxidation of sulfides to sulfones. The catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), optical profilometry, and contact angle measurements. Optimization of the catalytic conditions was performed using thioanisole as the standard molecule, resulting in optimal conditions of 50 degrees C, 1 h, 10 mg catalyst loading, 8 equivalents of H2O2 as oxidant, and acetonitrile as solvent. The results obtained were superior to those with crystalline NiWO4 (highly ordered), highlighting the crystallinity of the system as a key factor in the development of new catalysts. The catalyst exhibited high stability over successive catalytic cycles, and scaling up to 50 times was achieved. Additionally, the reaction scope showed good conversion for a variety of different sulfides, indicating the robustness of the catalyst. Analysis of the catalytic mechanism through scavenger tests and spectroscopic probes revealed that reactive oxygen species (ROS) are responsible for the oxidation of sulfides to sulfones. Furthermore, it was observed that the synergy between NiWO4 and chitosan is crucial for the effective generation of ROS in this reaction. (AU)

• Processo FAPESP: 23/12399-7 - Influência do doping de terras raras na estrutura do fotoânodo de BiVO4 para degradação de biomassa e geração de combustíveis
• Beneficiário: Lara Kelly Ribeiro da Silva
• Modalidade de apoio: Bolsas no Brasil - Programa Fixação de Jovens Doutores
• Processo FAPESP: 22/09715-1 - Oxidação de sulfetos via compósitos de g-C3N4/NiWO4 suportados em quitosana
• Beneficiário: Giovanna de Amorim Grasser
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs