Silver Nanocrystals-Decorated Polyoxometalate Singal-Walled Nanotubes as Nanoreactors for Desulfurization Catalysis at Room TemperatureHao Zhang, Xiaobin Xu, Haifeng Lin, Muhammad Aizaz Ud Din, Haiqing Wang and Xun Wang*

Department of Chemistry, Tsinghua University, Beijing 100084, China.

Correspondence and requests for materials should be addressed to X.W.. (email: wangxun@mails.tsinghua.edu.cn).

Electronic Supplementary Material (ESI) for Nanoscale.This journal is © The Royal Society of Chemistry 2017

Fig S1. The time series in the formation process of POM SWNTs. TEM image of POM SWNTs with various reaction time of (a) 0 min, (b) 15 min, (c) 30 min, (d) 45 min, (e) 120 min and (f) 180 min. The inset in (d) shows a ring in the product, which gives a top view of SWNTs. Scale bar: (a-f), 100 nm; inset of (a), 50 nm. Take a nanoroll from (b) and a nanotube from Fig. 1a to approximately calculate surface area. The surface area of cylinder follows S = πdl, and the nanoroll is calculated by S = 3πdl, for the 3 layers of the nanoroll on each side. It can be calculated that the surface area is about 0.015~0.025 μm2 for nanoroll and 0.010~0.020 μm2 for nanotube. The surface area of nanorolls and nanotubes are at the same scale. Considering the error in statistic, the rearrangement process in Scheme 1a can be proved.

Fig S2. TEM image of Ag-POM when AgNO3 concentration is increased to 4 g/L. Scale bar: 50 nm

Fig S3. TEM image of Ag-out-POM. The concentration of AgNO3 is increased to 4 mg/ml and the ratio of EtOH:cyclohexane is 6 ml : 3 ml. Scale bar: 100 nm

Fig S4. HRTEM pattern of Ag-POM. Scale bar: 10 nm. POM SWNTs show no lattice fringe in HRTEM pattern for their poor crystallinity.

Fig S5. FT-infrared spectroscopy of POM (upper curve) and Ag-POM (lower curve).

Fig S6. Powder XRD pattern of POM SWNTs and Ag-POM. Most peaks of both POM SWNTs and Ag-POM are broaden and hard to fit with a certain crystal structure, though a part of peaks labeled by vertical bars can fit some phosphotungstates. The three bars indicate peaks of Na5P3O10·6H2O (JCPDS: 10-0186), (NaPO3)3·6H2O (JCPDS: 11-0390) and H3PW12O40 (JCPDS: 50-0657).

2 4 62Theta (deg.)

2.51 nm

Fig S7. Small angle XRD pattern of Ag-POM shows a periodic distance of 2.51 nm, which indicates the distance of nearby two clusters on the cross section of SWNT. Take the diameter of SWNTs (9 nm) and perimeter equals to πd, the amount of POM clusters can be approximately calculated as:

= 11.3𝑛 =

𝜋𝑑𝑝𝑒𝑟𝑖𝑜𝑑𝑖𝑐 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒

0 500 10000.04

0.09

0.14TC

D sig

nal (

a.u.

)

Ag-POM

Temperature (oC)

POM

Fig S8. TPR profile of Ag-POM and POM SWNTs. A flow of 5 vol.% H2/Ar is used as carrier gas and heating rate is 5 oC/min.

Fig S9. TEM image of Ag-POM after recycling process of (a) 1 time and (b) 5 times. Scale bar: 100 nm.

a b

0 30 60 90

0

100

200

Rela

tive

Conc

entra

tion

(%)

Time (min)

A B C D

Fig S10. The control experiment to reveal the catalytic activity of each component. A: 30 mg POM SWNTs. B: 5 mg Ag NCs supported on 100 mg SiO2·xH2O, C: 30 mg Ag-POM, D: 5 mg Ag NCs. Then 30 μl DPS and 90 μl H2O2 was added into 10 ml n-octane and the reaction temperature is 20 oC.

Scheme S1 To confirm the spatial situation of Ag NCs in Ag-POM, suppose that all the NCs are on the outer surface of NTs. For an approximate calculation, the diameter ratio of NCs to NTs is supposed as 1:4. A single NC bind on the outer surface of NTs in a random direction and α stands for the angle of direction (0≤α≤90). TEM image is taken on a certain direction (top view). To let the outer NCs appears inside NTs in TEM image, α can be calculated as arccos (4/(4+1)) = 36.9o. That means just 41.0% (=36.9o/90o) NCs are inside NTs in TEM image. However most of NCs are inside NTs and seldom of them is tangent to NTs in figure 1. So it can be ensured that all the NCs are decorated inside the NTs. As a contrast, NCs in figure S3 fixs the 41.0% ratio and thus can be proved outside the NTs.

Table S1. ICP-AES datasample W Ag P Na

POM SWNTs 36.29% 0 0.4527% 3.208%Ag-POM 36.87% 1.528% 0.5223% 0.8331%

Ag-out-POM 36.56% 1.571% 0.4996% 0.8019%precipitate* 32.25% 1.331% 0.4577% 0.6811%

supernatant** 1.161% 0.1122% 0.01730% 0.03807%

* precipitate and ** supernatant after 5 times recycling.

Table S2. The assignment of FTIR spectraAg-POM POM Assignment*

2922 2923 CH2 asym. str.2853 2853 CH2 sym. str.1600 1601 O-H scissoring1490 1491 CH2N scissoring1465 1467 CH2 scissoring1377 1378 CH3 scissoring1080 1081 P-O asym. str.1035 1038 CH2N sym. str.944 946 W=Od sym. str.885 902 W-Ob-W sym. str.789 803 W-Oc-W sym. str.717 730 CH2 rocking

* asym. str., asymmetric stretching; sym. str., symmetric stretching

Table S3. TON of other reported ODS catalystsCatalyst Sub.a Temp.b Product TONc Ref.

DA-La(PW11)2 DPS 25 oC sulfone 1.2×103 1.WO3 DPS 25 oC sulfone 55 1.

(DODA)3PW12O40 DPS 50 oC sulfone 180 2.Chloroperoxidase MPS 37 oC sulfoxide 6.3×104 3.

Horseradish peroxidase MPS 37 oC sulfoxide 29 3.Lactoperoxidase MPS 37 oC sulfoxide 57 3.

Microsome peroxidase MPS 37 oC sulfoxide 3 3.(TBA)4Mo8O26 MPS 25 oC sulfoxide 242 4.

(TBA)2SeW2O14 MPS 20 oC sulfoxide 1.9×104 5.(Zr6O4)(AsW9O33)2 MPS 20 oC mixture 286 6.(Hf6O4)(AsW9O33)2 MPS 20 oC mixture 876 6.

(HDA)3PW12O40 DBT 50 oC sulfone 300 7.(DODA)3PW12O40 DBT 50 oC sulfone 660 2.

(DOHDA)3PW12O40 DBT 40 oC sulfone 571 8.H3PW12O40 DBT 50 oC sulfone 103 9.

(STA)3PW12O40 DBT 50 oC sulfone 4.2 10.(C18H37)2Me2NPW12O40 DBT 60 oC sulfone 319 11.

(DDA)9LaW10 DBT 30 oC sulfone 429 12.[(C18H37)

Me3N]PV2Mo10O40

DBT 60 oC sulfone 40 13.

MoO2/C thiophene 70 oC sulfone 0.0615 14.MoO3/Al2O3 thiophene 70 oC sulfone 0.0344 14.

K8Fe(PW9O34)2 THT 75 oC sulfoxide 60 15.

a Sub., substrate. b Temp., temperature. c TON, turnover number.

Table S4. The reaction condition and convert ratio of DBT ODS reactions. No. Cat. (ml)* Temp. (oC) Time (h) H2O2 (ul) Conversion(%)

0 POM ** 20 24 600 01 POM, 2.0 20 6 300 8.52 POM, 2.0 20 6 600 15.43 POM, 2.0 20 24 600 91.64 Ag-POM, 2.0 20 6 300 15.25 Ag-POM, 2.0 20 24 300 98.96 Ag-POM, 2.0 20 24 600 71.67 Ag-POM, 2.0 50 6 600 63.48 Ag-POM, 2.0 50 24 600 99.69 Ag-POM, 0.5 20 12 300 3.5

10 Ag-POM, 1.0 20 12 300 16.311 Ag-POM, 2.0 20 12 300 52.812 Ag-POM, 3.0 20 12 300 99.1

* cat., catalyst. 1.0 ml catalyst is amount to 8.5 mg Ag-POM.

** This group uses POM powder instead of nanotubes.

Reference

1. Zhao S, Jia Y, Song Y F. Applied Catalysis A General, 2013, 453(1):188-194.

2. Nisar A, Lu Y, Zhuang J, et al. Angewandte Chemie, 2011, 123(14):3187-92.

3. Fernández I, Khiar N. Chemical Reviews, 2003, 103(9):3651-705.

4. Yang C, Jin Q, Zhang H, et al. Green Chemistry, 2009, 11(9):1401-1405.

5. Kamata K, Hirano T, Ishimoto R, et al. Dalton Transactions, 2010, 39(23):5509-18.

6. Wallenfels B. Proceedings of the National Academy of Sciences of the United States of America, 1979, 76(7):3223-7.

7. Nisar A, Zhuang J, Wang X. Advanced Materials, 2011, 23(9):1130-5.

8. Qi W, Wang Y, Wen L D, et al. Chemistry, 2010, 16(3):1068.

9. Te M, Fairbridge C. Applied Catalysis A General, 2001, 219(1):267-280.

10. Huang D, Wang Y J, And L M Y, et al. Industrial & Engineering Chemistry Research, 2011, 45(6):págs. 1880-1885.

11. Dr C L, Dr Z J, Dr J G, et al. Chemistry, 2004, 10(9):2277–2280.

12. Xu J, Zhao S, Ji Y, et al. Chemistry, 2013, 19(2):709.

13. Lü H, Gao J, Jiang Z, et al. Chemical Communications, 2006, 2(2):150-152.

14. Zhuang L, Li Q, Chen S, et al. Journal of Materials Science, 2014, 49(16):5606-5616.

15. Okun N M, Anderson T M, Hill C L. Journal of the American Chemical Society, 2003, 34(22):3194-5.