Zinc-Blende CdS Nanocubes with Coordinated Facets for Photocatalytic Water Splitting

Transcription

1 Supporting Information Zinc-Blende CdS Nanocubes with Coordinated Facets for Photocatalytic Water Splitting Yangyang Zhang, a Lili Han, a Changhong Wang, b Weihua Wang,* c Tao Ling, a Jing Yang, a Cunku Dong, a Feng Lin* d and Xiwen Du* a 0 0 a. School of Materials Science and Engineering, Tianjin University, Tianjin 000, China b. School of Science, Tianjin University of Technology, Tianjin 00, China c. Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University, Tianjin, 000, China d. Department of Chemistry, Virginia Tech, Blacksburg, VA0, USA Corresponding authors: * xwdu@tju.edu.cn * whwangnk@nankai.edu.cn * fenglin@vt.edu

2 0 METHODS Synthesis of PbS nanocubes (NCs). The synthesis of nm-sizedpbs NCs was carried out via a hot-injection method. 0. g of PbCl was placed into a00 ml three-neck flask with 0 ml of oleylamine at room temperature. The resulted solution was then stirred with a magnetic stirring bar for min at 0 C. mg of sulfur powder was ultrasonically dissolved in ml of oleylamine at room temperature, and the resulting sulfur solution was injected into the Pb-oleylamine complex solution at 0 C. The mixture was aged for h at 0 C, resulting in a black colloidal solution. After cooling down, the black solution was centrifuged at,000 rpm for min and the supernatant was removed. The black deposit was washed with ethanol several times and finally dried in a vacuum desiccator at 0 C for h. Figure S. (a) TEM and (b) HRTEM images of the PbS nanocubes obtained at 0 C (c) and (d) are XRD pattern and EDS spectra of the products, respectively

3 0 Synthesis of core/shell nanocubes and CdS nanocubes. core/shell nanocubes were synthesized following the procedures previously reported for core/shellnps. In more detail,.mmol mmoland0mmol of Cd(Ac).H O was dissolved in a mixed solvent (ml of OA and 0 ml of ODE) separately and heated at 00 C for about minutes. The solution was injected to a 00-mL three-neck flask (equipped with a magnetic stirring bar) with ml of ODE suspension with -nm-sized PbS NCs (. g/l). The obtained mixture reacted for 0 min at different temperature (00~00 C) under Ar flow. The precipitate with different color was retrieved by centrifugation and washed with ethanol twice. Figure S. UV vis absorption spectra of the products at different reaction temperature

4 Figure S. (a)tem and HR-TEM images of Ni(OH) -CdS (b) Atomic-resolution annular dark field (ADF) image and(b) corresponding EELS mapping of Ni element of Ni(OH) -CdS (c)eds spectrum of Ni(OH) -CdS (d) XPS spectrum the sample of Ni(OH) /CdS. According to the binding energies of Ni p, the Ni p / located at. ev, so Ni(OH) was formed. 0 Transfer hydrophobic nanocrystals to aqueous solution.0 mg of the sample was first dispersed in 0 ml of chloroform, after which 00uL of ammonium sulfide (0wt%) and0 ml of methanamide were added to the solution subsequently under vigorous stirring. The striping was conducted at C for min. Then, the mixture was centrifuged and the supernatant was decanted. The deposit was washed with ethanol twice and finally dried in a vacuum desiccator at 0 C for h.

5 Figure S. XRD patterns and corresponding TEM images of wurtzite CdS nanoparticles(wz-nps),irregularly shaped zinc-blende CdS nanoparticles(zb-nps)and zinc-blende CdS nanocubes Figure S. (a)uv vis absorption spectra of PbS NCs, ZB-NPs and CdS NCs (b)plots of (αhυ) against hυof ZB-NPs and CdS NCs. 0

6 Figure S. TEM image of CdS NCs after hydrogen generation ( hours) Figure S. Comparison of the photocatalytic H -production activity of samples generated at 0 C, 0 C, 0 C and 00 C.All the samples were decorated with Ni(OH).

7 Figure S. Comparison of the photocatalytic H -production activity of samples Cd*, Cd*, Cd*,.mmol mmoland0mmol of Cd(Ac).H O was used for their synthesis separately. All the samples were decorated with Ni(OH). Table S. Relative content of Cd and Pb in the samples prepared at different temperature (The accuracy of Oxford INCA energy dispersive spectroscopy (EDS) module is +/- 0.%) Temperature( C) Cd/(Cd+Pb) Atomic % Pb/(Cd+Pb) Atomic %

8 Figure S. TEM images of CdS NCs after 00 C annealing Figure S0. (a) Geometric structure of CdS(b) band structure and PDOS of CdS bulk material.

9 Figure S. Slab models and LDOS of (a) (00)-Cd-term (b) (00)-S-term (c) ()-Cd-term and (d) ()-S-term surfaces.

10 Figure S. (a)band alignments between all (00) and () surfaces and (b) Band alignments between between (00)-Cd-term and ()-S-term with HSE hybrid functional. 0 Figure S. (a) HR-TEM image of Au-CdS clearly shows that the particles of Au are mostly photo-deposited on the corners of the nanocubes. (b) EDS spectrum of Au-CdS NCs demonstrates exist of gold and XPS of gold particles decorated CdS NCs is inserted 0

11 Figure S. (a)-(c)hr-tem pictures of Au-CdS captured from [], [00] and [0] zone axis,(a)(b)(c)models of the samples below, respectively. Red balls present the gold particles. 0 Figure S. (a) TEM image of Pt-CdS and (b)eds spectrum of Pt-CdS. Inserted HR-TEM image clearly show that the particles of Pt are mostly photo-deposited on the corners of the nanocubes. Namely, the photogenerated electrons are readily available for the reduction reaction on the {} facets. EDS spectrum demonstrate the presence of platinum.

12 Figure S. TEM image of Au-CdS obtained by thermal reduction Table S. Relative content of Cd and Ni in CdS-Ni(OH) (samples were diluted to meet the detection limit of the ICP-MS system) Cd (ug/l) Ni (ug/l) Ni/Cd wt% Ni(OH)/(Ni(OH)+CdS) wt % 0 CdS NCs. 0..0%.% ZB NPs.0..%.% WZ NPs...%.0% REFERENCES () Jin, J.; Na, H. B.; Yu, T.; Yu, J. H.; Kim, Y. W.; Wu, F.; Zhang, J. Z.; Hyeon, T. J. Am. Chem. Soc. 00,, () Wang, L.; Nemoto, Y.; Yamauchi, Y. J. Am. Chem. Soc. 0,, -. () Yan, Z. P.; Yu, X. X.; Han, A.; Xu, P.; Du, P. W. J. Phys. Chem. C 0,, -0. () Chen, X. P.; Chen, W.; Gao, H. Y.; Yang, Y.; Shangguan, W. F. Appl. Catal., B 0,, -.