- Pt-Rh/Al2O3 catalysts were prepared by successive incipient impregnations or coimpregnation. Characterization was achieved by H2 chemisorption and transmission electron microscopy. It was verified that method of preparation, ratio of metal weights and sequence of deposition are factors that result in very distinct catalysts.
Preparation methods; dispersion; catalysts
Catalyst |
%Pt |
%Rh |
D(%) |
|
2Pt-1Rh(a) |
2.0 |
1.0 |
5.1 |
18.0 |
4Pt-2Rh(a) |
4.0 |
2.0 |
20.7 |
4.4 |
6Pt-3Rh(a) |
6.0 |
3.0 |
18.3 |
5.0 |
1Pt-2Rh(a) |
1.0 |
2.0 |
10.7 |
8.6 |
2Pt-4Rh(a) |
2.0 |
4.0 |
6.1 |
15.1 |
3Pt-6Rh(a) |
3.0 |
6.0 |
8.0 |
11.5 |
2Rh-1Pt(b) |
1.0 |
2.0 |
13.5 |
6.8 |
4Rh-2Pt(b) |
2.0 |
4.0 |
14.4 |
6.4 |
6Rh-3Pt(b) |
3.0 |
6.0 |
4.2 |
21.9 |
1Rh-2Pt(b) |
2.0 |
1.0 |
11.9 |
7.7 |
2Rh-4Pt(b) |
4.0 |
2.0 |
10.0 |
9.2 |
3Rh-6Pt(b) |
6.0 |
3.0 |
26.6 |
3.4 |
Catalyst |
number of particle |
Particle Percentages |
||||
|
dp (nm) |
1 <dp (nm) |
3 <dp (nm) |
10 <dp (nm) |
dp >50 (nm) |
||
4Pt-2Rh |
999 |
93.9 |
5.9 |
0.2 |
- |
- |
6Pt-3Rh |
1740 |
6.2 |
71.3 |
21.1 |
1.4 |
- |
3Pt-6Rh |
868 |
- |
56.4 |
41.4 |
2.1 |
0.1 |
6Rh-3Pt |
474 |
- |
16.0 |
55.5 |
28.0 |
0.5 |
3Rh-6Pt |
596 |
71.8 |
27.5 |
0.5 |
0.2 |
- |
4Pt+2Rh(co) |
1860 |
86.2 |
6.7 |
6.1 |
0.05 |
- |
6Pt+3Rh(co) |
781 |
9.5 |
58.1 |
25.9 |
6.5 |
- |
3Pt+6Rh(co) |
447 |
74.4 |
18.4 |
4.1 |
3.0 |
- |
0p QH (nm) (b)
1
