posted on 2023-12-15, 01:29authored byAryane
A. Marciniak, Evelyn C. S. Santos, Richard J. Caraballo-Vivas, Odivaldo C. Alves, Marcelo E. H. Maia da Costa, Flávio Garcia, Claudio J. A. Mota
α-Fe2O3 nanorings (NRs) were decorated
with CeO2 and used as a catalyst for the direct synthesis
of dimethyl carbonate (DMC) from CO2 and methanol. The
α-Fe2O3 NR was prepared by microwave-assisted
hydrothermal synthesis followed by the precipitation of cerium nitrate
at different Ce/Fe atomic ratios (1:1, 1:2, and 1:5) and then calcined
at 400 °C. The characterization of the catalysts suggested the
interaction between the oxides upon modification of the α-Fe2O3 NR with the CeO2 nanoparticles, forming
mixed oxide interfaces. The synergy between CeO2 and α-Fe2O3 shows a maximum for the CeFe11 (1:1 atomic ratio)
catalyst, which also presented the highest concentration of oxygen
vacancies and specific surface area. This mixed oxide exhibited the
highest catalytic activity for the direct synthesis of DMC, which
may be interpreted in terms of the presence of oxygen vacancies and
the (110) exposed plane on the CeO2 surface. Furthermore,
the reuse of the catalyst showed good stability after three cycles.
The CeFe11 can also be used together with trichloromethyl acetate
(MTCA) as a dehydrating agent to shift the equilibrium and increase
the yield of DMC, indicating the potential of the system for the direct
synthesis of DMC from CO2 and methanol.