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C

ATHPRO, the Heterogeneous Catalysis and Catalytic

Processes group of the IST University of Lisbon,

participates in the Seventh Framework Programme of

the European Union (NPM3-SL-2012-309984) CEOPS (CO

2

loop for Energy storage and conversion to Organic chemistry

Processes through advanced catalytic Systems). The main task of

CATHPRO is to develop new zeolite-based catalysts formulations

for CO

2

hydrogenation into methane.

CO

2

as raw material for methane production

Increasing emissions of carbon dioxide is a well known critical

matter regarding the effect of greenhouse gases. Despite the

remarkable and intense search for energy alternatives and

renewable energy source-based processes, the consumption of

fossil fuels and the CO

2

emissions are still expected to grow in the

coming years.

Considering the sustainability problems associated to CO

2

sequestration and geological storage options, the use of carbon

dioxide as raw material for fuels and chemicals production

became an interesting alternative, thus mimicking the natural

carbon cycle. Among several possible transformations, the carbon

dioxide hydrogenation into methane (Sabatier reaction):

CO

2

+4H

2

CH

4

+2H

2

O is the most advantageous from a

practical point of view, with the potential substitution of natural

gas (NG) by this renewable methane using the existing NG

infrastructure. The hydrogen demand for this process is envisaged

to be supplied via water electrolysis promoted by renewable

sources of electricity (performed in daily low consumption

periods), or photoelectrolysis.

Available catalysts for CO

2

methanation usually involve group VIIIB

metals, mainly Ni, supported on several oxides. They were revealed

to be active but the search for new catalysts presenting

simultaneously high activity, very high CH

4

selectivity (avoiding CO

formation by RWGS) and good stability, should be pursued.

First CATHPRO research studies

The research studies at CATHPRO began with the preparation of

catalysts based on Ni and Ce species supported on an ultra-

stable partially exchanged HNaUSY zeolite (commercially

available). Several catalysts samples, containing different Ni

amounts, were prepared by ion-exchange and impregnation, and

deeply characterised by many techniques, as nitrogen adsorption,

hydrogen temperature programmed reduction (H2-TPR), UV-Vis

diffuse reflectance spectroscopy (DRS), transmission electron

microscopy (TEM) and X-ray diffraction (XRD), so that some

insights concerning the understanding of the catalytic promotion

could be obtained. Catalytic tests were carried out in a flow

tubular reactor, at atmospheric pressure, after a pre-reduction

treatment, under an 80% H2/N2 stream, at gas hourly space

The use of CO

2

as feedstock for production of valuable products, as fuel and

chemicals, is of increasing relevance

Catalysts for CO

2

methanation

30

I S S U E S E V E N

H O R I Z O N 2 0 2 0 P R O J E C T S : P O R TA L

www.horizon2020projects.com

P R O F I L E

S P E C I A L F E AT U R E : M AT E R I A L S

Fig. 1 CO

2

conversion and CH

4

selectivity, at GHSV = 43000 h-1, for the

USY (+), 10%NiO+USY (x), 2%NiUSHYEx(-), 2%NiUSHYImp(

),

5%NiUSHYImp(

), 10%NiUSHYImp(

) and 14%NiUSHYImp(

)

catalysts. Dashed line: thermodynamic equilibrium values