Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2011
SUPPLEMENTARY INFORMATION Visible light-driven CO2 reduction by enzyme coupled CdS nanocrystals# Yatendra S. Chaudhary,a,d Thomas W. Woolerton,a Christopher S. Allen,b Jamie H. Warner,b c c a 5 Elizabeth Pierce, Stephen W. Ragsdale and Fraser A. Armstrong* Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX DOI: 10.1039/b000000x a
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Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, Tel: +441865 272647; *E-mail:
[email protected] b Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, United Kingdom. c Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606,USA d Colloids and Materials Chemistry Department, Institute of Minerals and Materials Technology (CSIR), Bhubaneswar 751013, India
(311)
(220)
(111)
Intensity (a.u.)
15
calcined
as-synthesized 20
25
30
35
40
2θ (degree)
45
50
55
60
Figure S1. The XRD patterns of as-synthesised CdS QDs and calcined CdS
Absorbance (au)
20
500
550
60 0
650
700
750
800
Wavelength (nm) Figure S2. UV-vis absorption spectrum for CdS QDs
25
30
Determination of the amount of CODH attached to CdS nanocrystals: To determine the amount of co-attached CODH, 10 mg of CdS nanocrystals was dispersed in 5 ml of 0.35 M MES buffer solution (pH 6) in a pressure vessel, and sonicated for 20 min to ensure the formation of a stable suspension. Then, 13.9 µl of 184 µM CODH I (2.56 nmol) was introduced into the CdS nanocrystals suspension, followed by gentle stirring for 20 min to allow coattachment. The CODH-CdS nanocrystals suspension was then subjected to ultra-centifugation. The resulting supernatant was filtered through a membrane filter to assist the removal of any remaining traces of CdS. The supenatant solutions for each sample were subjected to UV-vis spectroscopy, and these spectra were compared to that of a control enzyme solution which had not been exposed to nanocrystals but had otherwise been through an identical procedure. The amount of co-attached CODH was determined from the difference in absorbance at 280 nm. 1
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Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2011
0.1
Absorbance (au)
Before co-attachment
After co-attachment
0.08 0.06 0.04 0.02 0 220
320
420
520
620
720
Wavelength (nm) Figure S3. Representative UV-vis absorbance spectra for solutions of CODH I in MES buffer (0.51 μM CODH I, 0.35 M MES, pH 6) before and after coattachment of CODH I with CdS QDs
Area CO peak / Area CH4 peak
5
3.0 2.5
y = 0.7078x + 0.0109
2.0 1.5 1.0 0.5 0.0 0.0
1.0
2.0
3.0
4.0
% CO Figure S4. Calibration plot for GC quantification of CO against an internal CH4 standard. 10
CO produced (µmol)
4
200 mM MES 500 mM MES 350 mM MES
3
2
1
0
0
1
2
3
4
Time (h) Figure S5. The amount of CO produced versus time for CODH-QD assemblies with different concentrations of MES (pH 6, 20 °C)
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