TY - JOUR
T1 - Bifunctional Co3O4/ZSM-5 Mesoporous Catalysts for Biodiesel Production via Esterification of Unsaturated Omega-9 Oleic Acid
AU - Núñez, Francisco
AU - Chen, Lifang
AU - Wang, Jin An
AU - Flores, Sergio Ordin
AU - Salmones, José
AU - Arellano, Ulises
AU - Noreña, Luis Enrique
AU - Tzompantzi, Francisco
N1 - Publisher Copyright:
© 2022 by the authors.
PY - 2022/8
Y1 - 2022/8
N2 - In the present work, two sets of the Co/ZSM-5 mesoporous catalysts with different acidity and Co loadings varying from 1 to 5 and 10 wt% were prepared using mesoporous ZSM-5-A (Si/Al = 50) and ZSM-5-B (Si/Al = 150) as support. X-ray diffraction (XRD) analysis showed that the Co3O4 phase was formed in the surface of catalysts and the reducibility of Co3O4 nanoparticles on the ZSM-5-B was greater in comparison with that on the ZSM-5-A solid. In situ FTIR of pyridine adsorption characterization confirmed that all of the Co/ZSM-5 catalysts contained both Lewis (L) and Brønsted (B) acid sites, with a relatively balanced B/L ratio ranging from 0.61 to 1.94. Therefore, the Si/Al molar ratio in ZSM-5 affected both the surface acidity and the cobalt oxide reducibility. In the esterification of unsaturated omega-9 oleic acid with methanol, under the optimal reaction conditions (temperature 160 °C, catalyst concentration 2 g/L, methanol/oleic acid molar ratio 30, and reaction time 180 min), the biodiesel selectivity reached 95.1% over the most active 10 wt% Co/ZSM-5-B catalyst. The higher esterification activity of the Co/ZSM-5-B catalysts can be correlated with the greater amount of B and L acid sites, the balanced B/L ratio, and the higher reducibility of Co3O4 nanoparticles. The oleic acid esterification reaction followed the bifunctional mechanism of combining metal function (dispersed Co3O4 with a greater reducibility) with the acidity function (both B and L acid sites with a relative balanced B/L ratio) on the catalysts, which may help in providing a deep understanding of the esterification pathways and benefiting the design of novel bifunctional catalysts for biofuel production.
AB - In the present work, two sets of the Co/ZSM-5 mesoporous catalysts with different acidity and Co loadings varying from 1 to 5 and 10 wt% were prepared using mesoporous ZSM-5-A (Si/Al = 50) and ZSM-5-B (Si/Al = 150) as support. X-ray diffraction (XRD) analysis showed that the Co3O4 phase was formed in the surface of catalysts and the reducibility of Co3O4 nanoparticles on the ZSM-5-B was greater in comparison with that on the ZSM-5-A solid. In situ FTIR of pyridine adsorption characterization confirmed that all of the Co/ZSM-5 catalysts contained both Lewis (L) and Brønsted (B) acid sites, with a relatively balanced B/L ratio ranging from 0.61 to 1.94. Therefore, the Si/Al molar ratio in ZSM-5 affected both the surface acidity and the cobalt oxide reducibility. In the esterification of unsaturated omega-9 oleic acid with methanol, under the optimal reaction conditions (temperature 160 °C, catalyst concentration 2 g/L, methanol/oleic acid molar ratio 30, and reaction time 180 min), the biodiesel selectivity reached 95.1% over the most active 10 wt% Co/ZSM-5-B catalyst. The higher esterification activity of the Co/ZSM-5-B catalysts can be correlated with the greater amount of B and L acid sites, the balanced B/L ratio, and the higher reducibility of Co3O4 nanoparticles. The oleic acid esterification reaction followed the bifunctional mechanism of combining metal function (dispersed Co3O4 with a greater reducibility) with the acidity function (both B and L acid sites with a relative balanced B/L ratio) on the catalysts, which may help in providing a deep understanding of the esterification pathways and benefiting the design of novel bifunctional catalysts for biofuel production.
KW - Co/ZSM-5
KW - bifunctional mechanism
KW - biodiesel
KW - esterification
KW - oleic acid
UR - http://www.scopus.com/inward/record.url?scp=85137376349&partnerID=8YFLogxK
U2 - 10.3390/catal12080900
DO - 10.3390/catal12080900
M3 - Artículo
AN - SCOPUS:85137376349
SN - 2073-4344
VL - 12
JO - Catalysts
JF - Catalysts
IS - 8
M1 - 900
ER -