School of Engineering and Science - Jacobs University

Number of particles
30 Types of sample
D
B
25
20
15
10
5
0
1.0 1.5 2.0 2.5 3.0 3.5
Particle size, nm
Fig. 4-5. Particles size distribution for B and D types of sample.
From the elemental analysis it was found, that the B-series sample contains 43.5 % C,
4.3 % N or 45 % cinchonidine, based on nitrogen content. From the TGA, the Pt
content was found to be 25 % thus differing from the 40 % metal content in the original
work [11] for 1.5 nm sized Pt cluster, probably because of the presence of
moisture/CO/CO2 and possibly acetic acid (30 %).
Elemental analysis of the D-catalysts before reaction (please see below) showed 16.6 %
C and 1.8 % N or 20 % cinchonidine, by making average between C and N. 63 % Pt
was found from TGA. The remaining content was attributed to moisture/CO/CO 2 . The
content of C and N on the D catalyst after 50 min of reaction was found to be 5.3 % and
0.8 %, correspondingly or 7 % of cinchonidine.
4.3.2 FTIR investigation of cinchonidine adsorbed on Pt
FTIR investigation of cinchonidine adsorbed on Pt was performed with cinchonidine
modified conventional Pt/Al 2 O 3 (Fig. 4-6) and cinchonidine modified Pt nanoclusters B
(Fig. 4-7) and D (Fig. 4-8) samples. The use of different Pt sample allows comparison
of adsorbed modes of the cinchonidine molecule of Pt crystals with different sizes,
starting from 1.2 (B-sample), passing 2.3 nm (D-sample) with 3.8 nm (conventional
alumina supported Pt) and ending with comparison of adsorption mode of cinchonidine
on microscopic Pt plane from the work of Ferri [76] and Zaera [77, 178]. In the Fig. 4-6
the region below 1300 cm -1 is not accessible of IR investigation, due to the contribution
of alumina background, whose FTIR spectrum can be found as an inset in the Fig. 5-5
from the chapter 5.
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