Supporting Information� Copyright Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, 2014

Palladium Nanoparticles Supported on Vertically OrientedReduced Graphene Oxide for Methanol Electro-OxidationLiming Yang,[a] Yanhong Tang,[b] Shenglian Luo,*[a] Chengbin Liu,*[a] Hejie Song,[a] andDafeng Yan[a]

cssc_201402352_sm_miscellaneous_information.pdf

1

Supporting Information

Figure S1. SEM images of Au/rGO electrodeposited from 0.2 gL1

GO and HAuCl4

with varied concentrations of (a) 0.5 mM and (b) 3 mM, the rGO/Au nanosheets

showing the evolution from horizontal to vertical orientation with increasing the

HAuCl4 concentration.

Figure S2. FTIR spectra of GO, rGO, and Pd/VrGO. The characteristic bands of GO

are observed at 3500~3700 cm1

(coupling OH stretching vibration, νOH),

2800~3100 cm1

(CH stretching vibrations, νCH), 1703 cm−1

(C=O stretching

vibration, νC=O), 1523 cm1

(C=C stretching vibration, νC=C), 1403 cm1

(OH

deformation vibration, OH), 1045 cm1

(CO stretching vibration, νCO). After the

electrochemical deposition of GO to electrodes, the intensities of the

oxygen-containing groups largely decreased in rGO and Pd/VrGO, meaning the

partial reduction of GO.

4000 3500 3000 2500 2000 1500 1000 5000

20

40

60

80

100

1523

C=CO-HC=OC-HO-H

Refl

ecti

on

(%)

Wave number / cm-1

rGO

VrGO/Pd

GO

1704 1045

C-O

1403

2

Figure S3. XPS spectra of Pd nanoparticles (a) and Pd/VrGO (b) in the Pd 3d region.

Pd nanoparticles shows two peaks that can be assigned to the Pd 3d3/2 (high-energy

band) and 3d5/2 (low-energy band) spin-orbit states of zero-valent Pd (Pd0). In

Pd/VrGO, each Pd 3d peak can be deconvoluted into two pairs of doublets assigned to

Pd0 and Pd

2+, indicating a bonding interaction between Pd nanoparticles and rGO in

Pd/VrGO.

Figure S4. SEM image of Pd/C electrocatalyst supported on a GC electrode, showing

closely packed fine Pd nanoparticles.

334 336 338 340 342 344

Pd2+

Pd03d3/2

3d5/2

Re

lati

ve

In

ten

sit

y /

a.u

.

Binding Energy /eV

(b)

332 334 336 338 340 342 344

Pd 3d 5/2

Pd 3d 3/2

Re

lati

ve

in

ten

sit

y /a

.u.

Binding Energy /eV

Pd0

(a)

3

Figure S5. CO-stripping measurement of the electrodeposited Pd nanoparticles in

N2-protected 1.0 M KOH solution at a scan rate of 50 mVs1

. Two CO oxidation

peaks are present, indicating that the Pd nanoparticles may have two different types of

sites for CO adsorption.

-0.9 -0.6 -0.3 0.0 0.3 0.6

-100

-50

0

50

100

J /A

g-1

Pd

E /V vs SCE

1st scan

2nd scan