The syn
thesis of me
thanol via ca
taly
tic hydrogena
tion of carbon oxides was evalua
ted in
two groups of Cu-Ga
2O
3-ZrO
2 ternary ca
talys
ts con
taining 2 w
t % .Cu. Copper was incorpora
ted in
the firs
t group ei
ther by incipien
t we
tness (IW) or by ion exchange (IE), bo
th on
the pure oxides (Ga
2O
3 and ZrO
2) and
the
x-Ga
2O
3/ZrO
2 mixed oxides (where
x = 1, 6 or 9 w
t % Ga
2O
3). In a second group of ma
terials galia was incorpora
ted on
to Cu/ZrO
2 previously dried or dried/calcined. The ca
taly
tic evalua
tions were performed in a
tubular microreac
tor a
t 3 MPa, 523 K, GHSV = 20,000 h
?1 using
two differen
t gas mix
tures. The firs
t mix
ture con
tained CO
2 and CO (
trong class=""boldFont"">M1trong>: H
2/CO
2/CO = 75/22/3), while in
the second one carbon monoxide was replaced by He (
trong class=""boldFont"">M2trong>: H
2/CO
2/He = 75/22/3).
The yield to methanol was progressively higher with gallia loading, but the best catalyst tested had an intermediate loading of Ga2O3 deposited onto a dried and calcined Cu/ZrO2 precursor which was obtained, in turn, by ion exchanging copper nitrate to the zirconia. The catalysts for which gallium were added to the dried and calcined IE Cu/ZrO2 precursor were the most stable.