Page 113 - 00. Complete Version - Progress Report IPEN 2014-2016

Renewable Energies | Progress Report 113

Effect of TiO2 Content on Oxidation
Ethanol Electrooxidation of ammonia
in Alkaline Media Using Pt using PtRh/C Pt/C
Nanoparticles Supported electrocatalysts:
on Physical Mixtures Fuel cell and
of Carbon and TiO2 as electrochemical
Electrocatalysts (Fig. 4). evaluation (Fig. 5). PtRh/C (90:10)

16 Intensity (Arb. units)
Figure 5. (a) Fitted XPS Pt 4f
14 core level spectra of the Pt/C, PtRh/C (50:50)
J (mA) / mgPt 10 8 6 catalyst. (b) Polarization and
12
PtRh/C 90:10, PtRh/C 50:50
power density curves of a 5
cm2DAFC with 2 mg metal
cm−2 in both anode and cath-
4
ode at 50▲C and using 1 mol
2 L−1 NH4OH and KOH ranging 80 78 76 74 72 70
0 from 0 mol L−1to 3 mol L−1. Binding energy (eV)
-0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1
E (V) vs Ag/AgCl Pt/C PtRh/C 90:10 PtRh/C 70:30 PtRh/C 50:50 Rh/C

NH OH mol L without KOH
-1
7 4 4.5
6 5 0.6 4.0
J (mA) / mgPt 4 3 Cell Potential / V 0.4 Power Density / mW cm -2 3.0
3.5
0.5
2.5
0.3
2.0
1.5
1.0
0. 1
1 2 0. 2 0.5
0 0 0
0 5 10 15 20 25 30 0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22
Time / minutes NH OH mol L + KOH 1 mol L -1
-1
4
0.6 4.5
Figure 4. a Cyclic voltammograms of Pt/(C+- 4.0
TiO2) electrocatalysts in the presence of 0.5 3.5
1mol L−1 ethanol and 1mol L−1 KOH saturat- 0.4 3.0
ed with N2 at a scan rate of 10 mV s−1. b Cur- Cell Potential / V Power Density / mW cm -2 2.5
rent-time curves at −0.35 V in the presence 0.3 2.0
of 1 mol L−1 ethanol and 1 mol L−1 KOH 0. 2 1.5
saturated with N2 at room temperature. 1.0
0. 1 0.5
0 0
0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22
NH OH mol L + KOH 3 mol L -1
-1
4
4.5
0.6 4.0
Cell Potential / V 0.4 Power Density / mW cm -2 3.0
0.5
3.5
2.5
0.3
2.0
1.5
0. 2
1.0
0. 1 0.5
0 0
0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22