Abstract:
The thermocatalytic hydrogenation of carbon dioxide (CO2
) to methanol is considered as
a potential route for green hydrogen storage as well as a mean for utilizing captured CO2
, owing
to the many established applications of methanol. Copper–zinc bimetallic catalysts supported on a
zirconium-based UiO-66 metal–organic framework (MOF) were prepared via slurry phase impregnation and benchmarked against the promoted, co-precipitated, conventional ternary CuO/ZnO/Al2O3
(CZA) catalyst for the thermocatalytic hydrogenation of CO2
to methanol. A decrease in crystallinity
and specific surface area of the UiO-66 support was observed using X-ray diffraction and N2
-sorption
isotherms, whereas hydrogen-temperature-programmed reduction and X-ray photoelectron spectroscopy revealed the presence of copper active sites after impregnation and thermal activation. Other
characterisation techniques such as scanning electron microscopy, transmission electron microscopy,
and thermogravimetric analysis were employed to assess the physicochemical properties of the
resulting catalysts. The UiO-66 (Zr) MOF-supported catalyst exhibited a good CO2 conversion of
27 and 16% selectivity towards methanol, whereas the magnesium-promoted CZA catalyst had a
CO2 conversion of 31% and methanol selectivity of 24%. The prepared catalysts performed similarly
to a CZA commercial catalyst which exhibited a CO2 conversion and methanol selectivity of 30 and
15%. The study demonstrates the prospective use of Cu-Zn bimetallic catalysts supported on MOFs
for direct CO2 hydrogenation to produce green methanol
Description:
SUPPLEMENTARY MATERIAL : FIGURE S1: Elementalmaps of Cu/ZnO/UiO66; FIGURE S2: Elemental maps of Cu/ZnO/Al2O3/MgO catalyst; FIGURE S3: Elemental maps of
commercial catalyst; FIGURE S4: XPS results of UiO-66: (a) full survey, (b) Zr3d, and O1s scans.
