Enhanced Electrocatalytic Activity of Carbon-Supported
Ordered Intermetallic Palladium–Lead (Pd<sub>3</sub>Pb) Nanoparticles
toward
Electrooxidation of Formic Acid
Takao Gunji
Seung Hyo Noh
Toyokazu Tanabe
Byungchan Han
Chiao Yin Nien
Takeo Ohsaka
Futoshi Matsumoto
10.1021/acs.chemmater.6b05191.s001
https://acs.figshare.com/articles/journal_contribution/Enhanced_Electrocatalytic_Activity_of_Carbon-Supported_Ordered_Intermetallic_Palladium_Lead_Pd_sub_3_sub_Pb_Nanoparticles_toward_Electrooxidation_of_Formic_Acid/4789438
Nanosized
ordered intermetallic Pd<sub>3</sub>Pb nanoparticles
(NPs)/carbon black (CB) (1–8 nm), Pd<sub>3</sub>Pb NPs/CB,
in which Pd<sub>3</sub>Pb has a Cu<sub>3</sub>Au-type structure and
its NPs are supported on CB, were prepared
by the polyol method under an air atmosphere and characterized using
X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning
transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy
(XPS). The XRD and XPS measurements confirmed the formation of ordered
intermetallic Pd<sub>3</sub>Pb NPs with a super lattice phase, and
the TEM and STEM images indicated a relatively uniform dispersion
of Pd<sub>3</sub>Pb NPs on the CB surface with an average size of
4.3 nm and an atomic ratio (Pd:Pb) of 75.9:24.1. The surface of the
as-prepared Pd<sub>3</sub>Pb NPs/CB was found
to be covered with the Pb (and its oxide) layer and to possess actually
no electrocatalysis for the electrooxidation of formic acid (FA).
However, this “inactive” as-prepared Pd<sub>3</sub>Pb
NPs/CB could be changed drastically to the “active”
one with a high level of electrocatalysis by the electrochemical treatment
using cyclic voltammetry, i.e., the pertinent electrooxidation of
the Pb surface coating in a 0.1 M HClO<sub>4</sub> aqueous solution.
The atomic-resolution STEM measurements confirmed that the surface
state of the “inactive” as-prepared Pd<sub>3</sub>Pb
NPs/CB can be controlled by changing the number of potential scans
employed in the electrochemical treatment. That is, when the potential
scan number is suitably chosen, the surface covered with the Pb coating
dissolves and becomes an active, ideal structure of Pd<sub>3</sub>Pb, and further scanning leads to a surface close to that of Pd NPs.
The thus electrochemically treated ideal Pd<sub>3</sub>Pb NPs/CB possessed
a largely higher level of electrocatalysis for the FA oxidation than
Pd NPs/CB, which could be explained reasonably on the basis of the
experimentally measured and/or theoretically calculated d-band center
values of both catalysts and CO binding energies on them.
2017-03-10 00:00:00
Pd 3 Pb NPs
XPS
Cu 3 Au-type structure
XRD
CO binding energies
intermetallic Pd 3 Pb NPs
intermetallic Pd 3 Pb nanoparticles
FA
Pb surface coating
CB
d-band center values
Pd 3 Pb
electrochemical treatment
0.1 M HClO 4
X-ray photoelectron spectroscopy
atomic-resolution STEM measurements
Enhanced Electrocatalytic Activity