Supporting Information for

Radiolytic synthesis of Au-Cu Bimetallic Nanoparticles Supported

on TiO2 and their Application in Water TreatmentZibin Hai1,2,3, Nadia EL Kolli1, Jiafu Chen2 and Hynd Remita1,4*

1Laboratoire de Chimie Physique, CNRS - UMR 8000, Université Paris-Sud, 91405 Orsay, France 2Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China3Anhui Academy of Environmental Science Research, Hefei, Anhui 230071, China4CNRS, Laboratoire de Chimie Physique, UMR 8000, 91405 Orsay, France

Figure S1 Picture of XPA-7 photochemical reactor.

XPA-7 photochemical reactor (purchased from Nanjing Xujiang Machine-Electronic Plant, China) was also used in the photocatalytic degradation tests. As is shown in Figure S1, a tube lamp is placed vertically in the center of a platform, surrounding is quartz cooling pipe, which can bring away the heat caused by the lamp and meanwhile permit thorough transmission of light ranging from ultraviolet to visible range. The optical filters vertically lie between the reactors and lamp. The reactors are placed outside of the platform, parallel to the tube lamp. The distance

Electronic Supplementary Material (ESI) for New Journal of Chemistry.This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2014

between the lamp and reactors is about 10 cm. The tube reactors are also made in quartz. Multiple magnetic agitators are installed just under the tube reactors.

200 300 400 500 6000

1

2

a b c d e

Abs

Wavelength (nm)Figure S2 UV-Vis absorption spectra of (a) AuCu1:1P25 supernatant before irradiation, (b)

AuCu1:1P25 supernatant after irradiation, (c) 1.25×10-4 M of HAuCl4 solution, (d) 1.25×10-4 M of CuCl2 solution, and (e) 2.5×10-2 M of urea solution after water bath at 90 ℃ for 2 hour.

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1

2

Filtration times 0 - 5

a b c d e fAb

s

Wavelength (nm)Figure S3 UV-Vis spectra of Au/P25DPU supernatants before and after several filtration cyclings.

Optical path: 10 mm.

The absorption peak at 262 nm obvioulsy decreased after the first filtration by a millipore filter

whose pore size is about 0.45 μm (see Figure S3). For the second filtration, the same filter was repeatly used. The decrease of the absorption peak at 262 nm was considerably smaller than the first time. This is reasonable because after filtration the number of larger TiO2 NPs decreases. Nevertheless, the smaller TiO2 NPs could not be filtrated (by the filter we used). The peak at 262 nm deceases in intensity with the increase of filtration times until reaching a plateau (Figure S3b-f).

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1

2

3

a b c

Abs

Wavelength (nm)Figure S4 UV-Vis absorption spectra of (a) supernatant of Au/P25DPU after irradiation, (b)

2.5×10-4 M of Au solution, and (c) 2.5×10-2 M of urea solution after water bath at 90 °C for 2 hours. Optical path: 10 mm.

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1

2

a b c d

Abs

Wavelength (nm)Figure S5 UV-Vis absorption spectra of (a) the supernatant of Cu/P25DPU before irradiation, (b)

supernatant of Cu/P25DPU after irradiation, (c) 2.5×10-4 M Cu solution, and (d) 2.5×10-2 M of urea solution after water bath at 90 °C for 2 hours. Optical path: 10 mm.

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1

2

a b c d e

Abs

Wavelength (nm)Figure S6 UV-Vis absorption spectra of (a) supernatant of AuCu13/P25DPU before irradiation, (b) supernatant of AuCu13/P25DPU after irradiation, (c) 1.25×10-4 M of Au solution, (d) 1.25×10-4 M of Cu solution, and (e) 2.5×10-2 M of urea solution after water bath at 90 °C for 2 hours. Optical path: 10 mm.

100 200 300 400 500

0.0

0.5

1.0

1.5

2.0

2.5

a b

Abs

Wavelength (nm)Figure S7 UV-vis absorption spectra of (a) the supernatant of Au/P25DP, and (b) 1.25×10–4 M

HAuCl4 solution. Optical path: 10 mm.

Figure S8 TEM images of the photocatalysts (a) Au/P25DPU-s, (b) AuCu1:3/P25DPU-s, (c) Au/P25DP at dose rate of 20 Gy/min; and (d) Au/P25DP at dose rate of 170 Gy/min.

BET Analysis

Nitrogen sorption isotherms were generated to investigate the porous structure and the

Brunauer-Emmett-Teller (BET) surface areas of the modified photocatalysts. The data are

shown in Figure S9. The sample AuCu1:3/P25 exhibits a typical-IV isotherm pattern and it

shows steep hysteresis loop at high relative pressure. The hysteresis loop as a result of

capillary condensation of N2 inside the pores is ascribed to the existence of mesopores. The

BET surface area was obtained as 47.0 m2 g–1. Compared to the reference P25 (51.4 m2 g–1), a

slight decrease in the BET surface area was found.

The pore size distribution for the modified P25 was obtained by the Barrett-Joyner-Halenda

(BJH) method and is presented in Figure S9b. The sample AuCu1:3/P25 shows bimodal pore

size distributions with a maximum pore diameter of 2.2 nm and 45.8 nm respectively,

indicating the presence of intra-aggregated pores and inter-aggregated pores (represented by

the hysteresis loop in the higher P/P0 range). Degussa P25 titania powders prepared by flame

hydrolysis of TiCl4 exhibited a monomodal pore-size distribution with a maximum pore

diameter at 2.33 nm. The significant difference in pore-size distribution for the modified

sample is probably due to the non-uniform drying stresses when the modified P25 slurry was

dried. BET Analysis

Figure S9 (a) N2 adsorption-desorption isotherms for the sample AuCu1:3/P25DPU. Inset: BET surface area plot of, (b) the corresponding pore size distribution.

94 92 90 88 86 84 82 80

2600

2700

2800

2900

3000

3100

3200Au4f

Inte

nsity

(CPS

)

Binding Energy (eV)Figure S10 Au4f region of the XPS spectra of sample AuCu1:3/P25.

960 950 940 930

17.5

18.0

18.5

19.0

19.5

Inte

nsity

(CPS

)

Kinetic Energy (eV)

Inte

nsity

(103 C

PS)

Binding Energy (eV)

900 905 910 915 920 925

CuLMM

Figure S11 Cu2p region of the XPS spectra of sample AuCu1:3/P25, after photocatalytic reaction under UV illumination. The inset is Auger CuLMM spectrum of the sample.

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0.5

1.0

1.5

MO 20ppm 5min 10min 15min 20min 25min 30min

Abs

Wavelength (nm)Figure S12 UV-vis absorption spectra of MO in photodegradation under UV illumination with the sample Au/P25.

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0.0

0.5

1.0

1.5

MO 20ppm 5min 10min 15min 20min 25min 30min

Abs

Wavelength (nm)Figure S13 UV-vis absorption spectra of MO in photodegradation under UV illumination with the sample AuCu1:1/P25

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0.0

0.5

1.0

1.5MO 20ppm0min5min10min15min20min25min

Abs

Wavelength (nm)Figure S14 UV-vis absorption spectra of MO in photodegradation under UV illumination with the sample AuCu1:3/P25

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0.0

0.5

1.0

1.5

0min 5min 10min 15min 20min 25min MO 20ppm

Abs

Wavelength (nm)Figure S15 UV-vis absorption spectra of MO in photodegradation under UV illumination with the sample Cu/P25

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-5

-4

-3

-2

-1

0

ln

C/C 0

Time (s)Figure S16 The first-order kinetics in photodegradation under UV illumination in the presence of P25 (filled square), Au/P25 (filled circle), AuCu1:1/P25 (filled triangle), AuCu1:3/P25 (open square), Cu/P25 (open circle), and no photocatalyst (open triangle).

Table S1 Rate constants of the pseudo first-order simulation of MO photodegradation under UV illumination.

Photocatalystk (rate constant)

(10–3 s–1)

ab (intercept)(s)

R (correlation coefficient)

P25 1.2±0.1 0.03±0.04 0.998

Au/P25 0.78±0.04 0.04±0.05 0.992

AuCu1:1/P25 1.5±0.1 0.13±0.12 0.986

AuCu1:3/P25 3.2±0.4 0.5 ±0.3 0.972

Cu/P25 1.7±0.1 0.03±0.07 0.996ab (intercept): calculated by linear fitting without through zero point.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

e

d

c

ba

k (1

0-3 s

-1)

Figure S17 Rate constants of the first-order kinetic of MO photodegradation under UV illumination with, (a) P25, (b) Au/P25DPU, (c) AuCu1:1/P25DPU, (d) AuCu1:3/P25DPU, and (e)

Cu/P25DPU.