The_Catalyst_Review_June_2023 - 18

Ethanol Dry Reforming over Bimetallic Ni-Containing Catalysts Based on Ceria-Zirconia
for Hydrogen Production
Ethanol reforming (steam or dry) is one of the more promising routes for producing H2
since it utilizes both a critical greenhouse
gas (CO2) and a bio alcohol derived from biomass. Currently, ethanol dry reforming (EDR) is considered the more attractive process
because it is less energy-demanding and, thus, ecologically and economically more attractive.
Catalysts employed in EDR are typically composed of nickel deposited over different supports, although they suffer from active
metal sintering and the formation of carbon followed by deactivation. One approach to overcoming the deactivation problem is
to use nanocrystalline oxides with high oxygen mobility as a support for nickel catalysts, which facilitates the gasification of coke
precursors. Another way to increase the catalytic activity is to use bimetallic catalysts, containing particles of two different metals or
their alloys deposited on different supports. Herein, the authors combine both approaches - using catalysts containing two metals
supported on oxides with high oxygen reactivity.
As EDR catalysts, bimetallic Ni-Co
catalysts based on ceria-zirconia
supports with varying Ce/Zr ratios
were investigated. Furthermore, the
influence of the supported metals
interaction and the Ce/Zr ratio in the
support on the catalytic activity in EDR
were assessed. These workers began by
synthesizing Mixed Ce-Zr oxides with a
fluorite structure using the solvothermal
method in a supercritical medium of
isopropanol. The prepared mixed
oxides Ce0.5
O2
Zr0.5 O2 and Ce0.75
Zr0.25
were used as supports for 5 wt%Ni
and bimetallic 2.5 wt%Ni+2.5 wt%Co
catalysts. The catalysts were thoroughly
characterized (specific surface area,
shape, particle size, phase composition,
and surface atomic composition) before
being tested in ethanol dry reforming.
The dependences of the conversion
of C2
and H2
H5OH and CO2
, and the H2
, the yield of CO
/CO ratio were then
measured (Figure 1).
Efforts were then directed at measuring
the effect of the supported metal
interaction as well as the effect of the
Ce/ Zr ratio in the support upon the
catalytic activity. The presence of nickel
in the composition of the catalyst was
found to be necessary for high catalytic
activity. It was also shown that the
addition of cobalt does not increase
catalytic activity and stability but instead
helps to decrease carbon deposition
and significantly reduces the carbon
formation rate during ethanol dry
reforming compared to the use of the
monometallic nickel material. Fedorova
V, Bespalko Y, Arapova M, et al. (2023).
ChemCatChem, doi.org/10.1002/
cctc.202201491
Figure 1. The dependences of C2
H5OH conversion (a), CO2
conversion (b), CO yield
(c), H2 yield (d), CH4 yield (e), H2/CO ratio (f) on reaction temperature.
18
The Catalyst Review
June 2023

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