2.3. Catalytic activity test
Activity measurements were carried out in a continuous-flow,
fixed-bed reactor. A 0.5 g catalyst diluted with 0.5 g quartz sand
(both in 20–40 mesh) was packed into the stainless steel tubular
reactor (5 mm i.d.). Prior to the catalytic measurements, the catalyst was reduced in a stream of 10% H2/N2(30 ml/min) at 573 K
for 3 h under atmospheric pressure. Then the reactor was cooled
to 433 K and the reactant gas (CO2:H2= 1:3, molar ratio) flow of
15 ml/min was introduced, raising the pressure to 3.0 MPa and
the temperature to a given temperature. Effluent products were
analyzed on-line with a gas chromatograph (Agilent 6820). Conversion and selectivity values were calculated by mass-balance
methods and the steady-state values are quoted as the average of
four different analyses taken after 4 h on stream operation.