Unraveling Surface Plasmon Decay in Core Shell Nanostructures towards Broadband Light-Driven Catalytic Organic Synthesis

Transcription

1 Supporting Information Unraveling Surface Plasmon Decay in Core Shell Nanostructures towards Broadband Light-Driven Catalytic Organic Synthesis Hao Huang,, Lei Zhang,, Zhiheng Lv, Ran Long, Chao Zhang, Yue Lin, Kecheng Wei, Chengming Wang, Lu Chen, Zhi-Yuan Li,, Qun Zhang,, * Yi Luo, and Yujie Xiong, * Hefei National Laboratory for Physical Sciences at the Microscale, ichem (Collaborative Innovation Center of Chemistry for Energy Materials), School of Chemistry and Materials Science, Hefei Science Center (CAS), Synergetic Innovation Center of Quantum Information & Quantum Physics, and National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui , P.R. China Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing , P.R. China College of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong , China *Corresponding author. yjxiong@ustc.edu.cn; qunzh@ustc.edu.cn These authors contributed equally. S1

2 1. Experimental Procedure: Synthesis of Au nanorods. The Au nanorods (Au NRs) were synthesized by following the seed-mediated growth method developed by El-Sayed et al.. S1 The suspension of the Au NRs was centrifuged three times at 8,000 rpm for 10 min. The precipitation was redispersed in deionized water, and the concentration of the Au NRs was 1 mg ml -1, which was measured by inductively coupled plasma mass spectrometry (ICP-MS). 2. Sample characterizations: Prior to the electron microscopy characterizations, a drop of the aqueous suspension of particles was placed on a piece of carbon-coated copper grid and dried under ambient conditions. The TEM and HRTEM images and the corresponding EDS mapping analyses were taken on a JEOL JEM-2100F field-emission high-resolution transmission electron microscope operated at 200 kv. The HRTEM and HAADF-STEM images and the corresponding EDS mapping analyses were taken on a JEOL ARM-200F field-emission transmission electron microscope operated at 200 kv. The UV-Vis extinction spectra were recorded on an Agilent Technologies Cary 60 spectrometer. The concentrations of elements were measured with a Thermo Scientific Plasma Quad 3 inductively-coupled plasma mass spectrometry (ICP-MS) after dissolving them with a mixture of HCl and HNO 3 (3:1, volume ratio). S2

3 Figure S1. TEM image of Au nanorods. The Au nanorods have an average diameter of 16 nm and length of 66 nm with an aspect ratio of 4.1. S3

4 Figure S2. HAADF-STEM images on the same sample region as Figures 1d and 1e by prolonging exposure time on Au. (a) HAADF-STEM image, and (b) atomic-resolution image taken from the edge region marked by the box in panel a. The Pd shell diminishes with increasing the contrast by prolonging exposure time on Au. S4

5 Figure S3. Structural and compositional analyses on Au NRs Pd 7L core shell nanostructures. (a) TEM image, (b) HRTEM image recorded along [001] orientation, and (c) STEM and EDS mapping profiles of a single nanostructure: Pd (green) and Au (red). As indicated by the HRTEM image in Figure S3b, the resulting bar-like nanostructures are exclusively enclosed by {100} facets. The lattice fringes with a period of 2.0 Å can be well assigned to the {200} spacing of fcc Pd. Based on the contrast and the lattice constant, we can determine that the shell contains 7 layers of Pd atoms. The STEM and EDS mapping profiles (Figure S3c) further confirm the core shell structures with Au cores and Pd shells. S5

6 Figure S4. Structural and compositional analyses on Au NRs Pd 14L core shell nanostructures. (a) TEM image, (b) HRTEM image recorded along [001] orientation, and (c) STEM and EDS mapping profiles of a single nanostructure: Pd (green) and Au (red). As indicated by the HRTEM image in Figure S4b, the resulting bar-like nanostructures are exclusively enclosed by {100} facets. The lattice fringes with a period of 2.0 Å can be well assigned to the {200} spacing of fcc Pd. Based on the contrast and the lattice constant, we can determine that the shell contains 14 layers of Pd atoms. The STEM and EDS mapping profiles (Figure S4c) further confirm the core shell structures with Au cores and Pd shells. S6

7 Figure S5. Structural and compositional analyses on Au NRs Pd 27L core shell nanostructures. (a) TEM image, (b) HRTEM image recorded along [001] orientation, and (c) STEM and EDS mapping profiles of a single nanostructure: Pd (green) and Au (red). As indicated by the HRTEM image in Figure S5b, the resulting bar-like nanostructures are exclusively enclosed by {100} facets. The lattice fringes with a period of 2.0 Å can be well assigned to the {200} spacing of fcc Pd. Based on the contrast and the lattice constant, we can determine that the shell contains 27 layers of Pd atoms. The STEM and EDS mapping profiles (Figure S5c) further confirm the core shell structures with Au cores and Pd shells. S7

8 Figure S6. Pd/Au moral ratios in Au NRs Pd core shell nanostructures (measured by ICP-MS) as a function of the volume of K 2 PdCl 4 added during the synthesis. S8

9 Figure S7. UV-vis extinction spectra of bare Au nanorods and Au NRs Pd core shell nanostructures with varied Pd shell thicknesses. S9

10 Figure S8. Calculated extinction, absorption, and scattering cross sections of Au nanorods and various Au NRs Pd core shell nanostructures with incident light along longitudinal and transverse directions. (a) Extinction, L mode; (b) absorption, L mode; (c) scattering, L mode; (d) extinction, T mode; (e) absorption, T mode; and (f) scattering, T mode. The wavelengths of plasmonic band maxima are listed in each subgraph. In the DDA calculations, the diameters as well as the widths, lengths, and shell thicknesses of Au NRs-Pd are shown in Table S1, and the medium is the air. S10

11 Figure S9. Plots of the relative field amplitude along longitudinal and transverse directions for Au nanorods and various Au NRs Pd core shell nanostructures. (a) Au NRs, L mode; (b) Au NRs Pd 2L, L mode; (c) Au NRs Pd 7L, L mode; (d) Au NRs Pd 14L, L mode; (e) Au NRs Pd 27L, L mode.; (f) Au NRs, T mode; (g) Au NRs Pd 2L, T mode; (h) Au NRs Pd 7L, T mode; (i) Au NRs Pd 14L, T mode; and (j) Au NRs Pd 27L, T mode. The DDA calculation models are the same as those used for Figure S8. The incident-light wavelengths are set at the plasmonic band maxima in Figure S8. S11

12 Figure S10. Thermally-driven catalytic hydrogenation performance by various Au NRs Pd core shell nanostructures in the dark with thermostatic control at 70 ± 1 C. Reaction conditions: 0.2-mmol styrene and catalyst containing mg Au in 1-mL H 2 O, 1-atm 100 % H 2, 1 hour. S12

13 Figure S11. Thermally-driven catalytic hydrogenation performance by Au NRs Pd 14L core shell nanostructures in the dark as a function of reaction temperature. Reaction conditions: 0.2-mmol styrene and catalyst containing mg Au in 1-mL H 2 O, 1-atm 100 % H 2, 1 hour. S13

14 Figure S12. Catalytic hydrogenation performance by Au NRs Pd 14L core shell nanostructures under full-spectrum light irradiation with thermostatic control at various temperatures between 0 70 C. Reaction conditions: 0.2-mmol styrene and catalyst containing mg Au in 1-mL H 2 O, 1-atm 100 % H 2, 1 hour. S14

15 Figure S13. Hot-electron contribution by Au NRs Pd 14L core shell nanostructures in styrene hydrogenation under full-spectrum light irradiation at various temperatures between 0 20 C. The calculations are performed by subtracting the yield in the dark at a certain temperature (Figure S11) from that under full-spectrum light irradiation with thermostatic control at the same temperature (Figure S12). S15

16 Figure S14. Ultrafast transient absorption (TA) spectra of bare Au NRs dispersed in water. (a) TA signal (probed at 700 nm) as a function of probe delay, recorded for L mode with a 650-nm pump. (b) TA signal (probed at 520 nm) as a function of probe delay, recorded for T mode with a 480-nm pump. S16

17 Table S1. Pd shell thicknesses, nanocrystal sizes, and Pd/Au molar ratios of various Au NRs Pd core shell nanostructures. Samples Estimated Pd layers (n) by TEM Outer length (nm) Outer diameter or width (nm) Pd/Au molar ratio calculated from size and n Pd/Au molar ratio by ICP-MS Au NRs-Pd 2L Au NRs-Pd 7L Au NRs-Pd 14L Au NRs-Pd 27L S17

18 Table S2. Catalytic conversion of styrene to ethylbenzene by various Au NRs Pd core shell nanostructures under light irradiation without thermostatic control. Reaction conditions: 0.2-mmol styrene and catalyst containing mg Au in 1-mL H 2 O, 1-atm 100 % H 2, 1 hour, no additional heating. The data is also listed in Figure 2a in main text. Conversion of styrene to ethylbenzene Full spectrum (%) 400 < λ < 700 nm (%) λ > 700 nm (%) Au NRs-Pd 2L Au NRs-Pd 7L Au NRs-Pd 14L Au NRs-Pd 27L S18

19 Table S3. Catalytic conversion of styrene to ethylbenzene by various Au NRs Pd core shell nanostructures under light irradiation with thermostatic control at 20 ± 1 C or at the same temperature in the dark. Reaction conditions: 0.2-mmol styrene and catalyst containing mg Au in 1-mL H 2 O, 1-atm 100 % H 2, 1 hour, 20±1 C. The data are also listed in Figure 2b in the main text. Conversion of styrene to ethylbenzene Dark (%) Full spectrum (%) 400 < λ < 700 nm (%) λ > 700 nm (%) Au NRs-Pd 2L Au NRs-Pd 7L Au NRs-Pd 14L Au NRs-Pd 27L S19

20 References S1. Nikoobakht, B.; El-Sayed, M.A. Chem. Mater. 2003, 15, S20