148
Y. Li et al.
Fig. 4.44 a Oxygen reduction polarization curve of BCNTs and Pt/C at 0.1 M NaOH, b HOMO-1
of BCNTs (5,5), c Chronoampelarization curves of BCNTs and Pt/C catalysts against methanol in
0.1 mol L −1 NaOH solution saturated with O 2 , d Chronoampelarization curves of BCNTs and Pt /
C catalysts against CO in 0.1 mol L −1 NaOH solution saturated with O 2 [371]
nitrogen content in the catalyst under the same conditions. Zhu et al. [332] used
melamine (C3H6N6) as the precursor to prepare NCNTs with high N content, and
the nitrogen content was close to 20%. When using these NCNTs with high N content
for ORR catalyst, its ORR performance did not improve compared with that of
NCNTs with low content [334, 342]. In the case of very low N content, NCNTs still
has considerable ORR performance. Borghei et al. [343] coated CNTs treated with
polyaniline (PANI) at high temperature to obtain NCNTs with N content as low as
0.56%, still showing considerable ORR activity. The ORR properties of NCNTs with
different N content are listed in Table 4.1.
Table 4.1 Comparison of
kinetic current density of
different crystal planes of Pt
and Pd at 0.9 V (vs. RHE) in
0.1 M HClO 4 solution [148].
Reprinted with permission.
[148] Copyright (2009)
American Chemical Society
Pt (hkl) j ORR,0.9 V /mA cm −2 Pd (hkl) j ORR,0.9 V /mA cm −2
(100)
1.67
(100)
0.43
(111)
0.12
(111)
0.59
(110)
0.4
(110)
0.60