Supporting information for:

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1 Supporting information for: CdTe/CdS Core/Shell Quantum Dots co-catalyzed by Sulfur Tolerant [Mo 3 S 13 ] 2- Nanoclusters for Efficient Visible Light-driven Hydrogen Evolution Dongting Yue, Xufang Qian, Zichen Zhang, Miao Kan, Meng Ren and Yixin Zhao* School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai (China) *Address corresponding to Prof. Yixin Zhao: yixin.zhao@sjtu.edu.cn. Number of pages: 13 Number of tables: 1 Number of figures: 5 Table of contents Table S1. The composition of the CdTe QDs, CdTe/CdS QDs and [Mo 3 S 13 ] 2- -CdTe/CdS QDs determined by ICP-AES measurement. Figure S1. XRD patterns of pure (NH 4 ) 2 Mo 3 S 13 nh 2 O. Figure S2. Photoluminescence decays at various ph values, containing CdTe/CdS QDs (CdTe, M), H 2 A (20 mg/ml) and [Mo 3 S 13 ] 2- clusters ( M). Figure S3. UV-vis absorption spectra of pure [Mo 3 S 13 ] 2- clusters and CdTe/CdS QDs with different concentration of [Mo 3 S 13 ] 2- clusters (0 to M) in water. Figure S4. Luminescence spectra of CdTe/CdS QDs with different concentration of [Mo 3 S 13 ] 2- clusters (0 to M) in water (excitation wavelength: 410 nm). Figure S5. H 2 evolution of CdTe/CdS under the optimized conditions. S1

2 EXPERIMENTAL SECTION Chemicals. Cadmium chloride (CdCl 2 ), 3-Mercaptopropionic acid (3-MPA), sodium borohydride (NaBH 4 ) (98%), potassium hexachloroplatinate (IV) were obtained from Aladdin Industrial Corporation. Tellurium powder (99.9%), ascorbic acid (H 2 A), sodium hydroxide, hydrochloric acid, carbon disulfide, toluene and ethanol were purchased from Sinopharm Chemical Reagent Co., Ltd. L-glutathione reduced (GSH) (Sigma-Aldrich, 98.0%) was obtained from InnoChem Science&Technology Co., Ltd. Ammonium heptamolybdate tetrahydrate ((NH 4 ) 6 Mo 7 O 24 4H 2 O) was purchased from Xiya Reagent. Photocatalytic H 2 Generation. The H 2 production of photocatalytically splitting water was carried out in a Pyrex reaction vessel connected to a closed gas circulation and evacuation system. An aqueous solution containing CdTe/CdS QDs (CdTe, M), H 2 A (20 mg/ml), and [Mo 3 S 13 ] 2- clusters ( M) were added to the vessel with magnetic stirring. The total volume of the aqueous solution was 20 ml. Before irradiation, the ph of the solution was adjusted by 1.0 M NaOH or 1.0 M HCl solution. The solution was then degassed for 20 min, followed by irradiation with a 300 W Xe lamp (Ceaulight, CEL-HXF-300) fitted with a 420 nm cutoff filter. The reactant solution was stirred and maintained at room temperature by a flow of cooling water during the photocatalytic reaction. The amount of evolved H 2 was monitored via online gas chromatography (Ceaulight, GC 7900, MS-5 A column, TCD, N 2 carrier). The desired concentration of the reaction system was achieved by adjusting ph and dissolving different amount of H 2 A, CdTe/CdS QDs and [Mo 3 S 13 ] 2- clusters into 20 ml of the mixed aqueous solution. Characterization. The morphologies of samples were characterized by transmission electron microscopy S2

3 (TEM) and high-resolution transmission electron microscopy (HRTEM) which were performed on a JEM-2100F microscope. X-ray diffraction (XRD) patterns of the samples were performed on an automated Bruker D8 Advance X-ray diffractometer with Cu-Kα radiation. The data were recorded at a scan rate of 10 deg min 1 in the 2θ range from 10 to 80. The X-ray photoelectron spectroscopy (XPS) analysis was carried out on a Kratos Axis Ultra DLD spectrometer with a monochromatic Al K α source ( ev). All binding energies were referenced to the C 1s peak (284.8 ev) of adventitious carbon on the analyzed sample surface. The composition of samples was determined by inductively coupled plasma optical emission spectrometer (ICP-AES, icap6300, Thermo). Photoluminescence (PL) spectra were recorded on a F-380 fluorescence spectrophotometer (F-380, Tianjin Gangdong SCI.&TECH. Development CO, LTD) at room temperature, respectively. The excitation wavelength for all steady-state PL measurements was set to 410 nm. Time-resolved PL decay measurements were carried out on a Fluorescence Lifetime Spectrometers (QM/TM/IM, Photon Technology International, USA). S3

4 Calculation of turnover number (TON) TON is molecules of H 2 per molecule of CdTe QDs or [Mo 3 S 13 ] 2- cluster, which is determined using the following equations: (1) where the number of H 2 molecules is generated by fitting the area of H 2 determined by GC measurement. The number of individual CdTe QDs is determined by counting the initial number of CdTe QDs added in the reaction system. The number of [Mo 3 S 13 ] 2- clusters is obtained by referring to 1.84 mmol/l [Mo 3 S 13 ] 2- clusters which was determined by ICP-AES measurement. The calculation of V m,h2,25 was determined by van der waals equitation as below: (2) where R = cm 3 Pa mol 1 K 1 ; T = K; p = Pa; b = 26.6 cm 3 mol 1 ; a = cm 6 Pa mol 2. S4

5 The concentration of CdTe QDs The diameter (D) and extinction coefficient (ε) of the QDs are calculated by the equations reported by Peng and coworkers 1 : (3) (4) (5) where D (nm) is the diameter or size of a given sample; λ is the wavelength of the first excitonic absorption peak (from low energy) of the corresponding sample; ε is the extinction coefficient of the corresponding sample; Abs is the absorbance of sample; L (1 cm) is the length of cuvette in the direction of irradiation and c is concentration of the corresponding sample. The diameter (D) and extinction coefficient (ε) of the prepared CdTe QDs were calculated to be ~2.4 nm and L mol 1 cm 1. The concentration of the CdTe QDs was determined as M using the Beer-Lambert law. S5

6 Table S1. The composition of the CdTe QDs, CdTe/CdS QDs and [Mo 3 S 13 ] 2- -CdTe/CdS QDs determined by ICP-AES measurement. Sample Cd S Te Mo CdTe QDs (mg/l) CdTe/CdS QDs (mg/l) [Mo 3 S 13 ] 2- -CdTe/CdS QDs (mg/l) S6

7 Figure S1. XRD patterns of pure (NH 4 ) 2 Mo 3 S 13 nh 2 O. S7

8 Figure S2. Photoluminescence decays at various ph values, containing CdTe/CdS QDs (CdTe, M), H 2 A (20 mg/ml) and [Mo 3 S 13 ] 2- clusters ( M). S8

9 Figure S3. UV-vis absorption spectra of pure [Mo 3 S 13 ] 2- clusters and CdTe/CdS QDs with different concentration of [Mo 3 S 13 ] 2- clusters (0 to M) in water. S9

10 Figure S4. Luminescence spectra of CdTe/CdS QDs with different concentration of [Mo 3 S 13 ] 2- clusters (0 to M) in water (excitation wavelength: 410 nm). S10

11 Figure S5. H 2 evolution of CdTe/CdS under the optimized conditions. S11

12 REFERENCES (1. Yu, W. W.; Qu, L.; Guo, W.; Peng, X., Experimental determination of the extinction coefficient of CdTe, CdSe, and CdS nanocrystals. Chem. Mater. 2003, 15 (14), S12