Stepwise methane to methanol conversion: Effect of copper loading on the formation of active species in copper-exchanged mordenite

Autor(es)

Mizuno, Stefanie C. M. ^[1] ; Dulnee, Siriwan ^[1] ; Pereira, Tassia C. P. ^[1] ; Passini, Ricardo J. ^[1] ; Urquieta-Gonzalez, Ernesto A. ^[1] ; Gallo, Jean Marcel R. ^[2] ; Santos, Joao B. O. ^[1] ; Bueno, Jose M. C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Chem Engn, Rod Washington Luis, Km 235, CP 676, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Chem, Renewable Energy Nanotechnol & Catalysis Grp Gree, Rod Washington Luis, Km 235, CP 676, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CATALYSIS TODAY; v. 381, p. 13-25, DEC 1 2021.
• Citações Web of Science: 0

Resumo

This work investigates the influences of Cu content, Si/Al ratio, and sample preparation method on the active Cu species in mordenite (MOR). The Cu/MOR prepared by multiple Cu-exchange procedures showed an optimum Cu/Al ratio for the formation of the most active species for methanol formation. XANES spectra indicated that isolated Cu+ species were formed after CH4 interaction and were re-oxidized under a flow of water steam. The Cu-MOR samples obtained by ion-exchange method presented well-dispersed CuO in the zeolite pores, while samples obtained by impregnation method presented segregated CuO and were inactive for CH4 activation. The methodology used for in situ UV-vis spectra analyses indicated that different Cu species were active for CH4 oxidation. Isolated Cu2+ species were not involved in CH4 activation at temperatures lower than 300 degrees C. The isolated Cu2+ species were partially hydrolyzed by O-2 treatment and species like {[}CuOH](+) and {[}CuOx](n) or polynuclear Cu2+-oxyhydroxide were formed. The formation of polynuclear species in substitution of di-copper would impact the specific activity with the Cu content and decrease the activity for methanol production. (AU)

• Processo FAPESP: 16/02128-2 - Desenvolvimento de novos sistemas catalíticos para a biorrefinaria
• Beneficiário: Jean Marcel Ribeiro Gallo
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 18/26459-3 - Zeólitas trocadas com sítios únicos de CuxOy para a oxidação parcial de metano em metanol: o efeito da estrutura da zeólita e outros óxidos metálicos na atividade de um único sítio
• Beneficiário: Tássia Caroline Passos Pereira
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 18/01258-5 - Novos processos catalíticos e fotocatalíticos para a conversão direta de metano e CO2 em produtos
• Beneficiário: José Maria Correa Bueno
• Modalidade de apoio: Auxílio à Pesquisa - Temático