Tandem photocatalysis of graphene stacked SnS2 nanodiscs and ...
Supporting information (SI)
Tandem photocatalysis of graphene stacked SnS2 nanodiscs and nanosheets with efficient carrier separation Himani Chauhan, Kiran Soni, Mukesh Kumar and Sasanka Deka* Department of Chemistry, University of Delhi, North campus, Delhi-110007, India Fax: (+) 91-11-27667206, E-mail: [email protected], [email protected]
Equations used for band gap determination1 (h)n = A*(h − Eg)
(1)
where h is the photon energy, n is an index characterizing the type of optical transition, A* is a certain frequency independent constant, Eg is optical band gap and is absorption coefficient defined by Beer-Lambert law as follows
= −lnA/l
(2)
Where l is optical path length and A is absorbance. Optical band gap and the nature of transition are determined by ploting (Ah) n vs. hv, where n = 2 for direct transition. Equations used for dye degradation percentage2 D
(3)
Where Ao is the initial absorbance at adsorption-desorption equilibrium before the addition of the catalyst and At is the absorbance of remnant dye at definite intervals of time‘t’ after the addition of the photocatalyst. Equations used for apparent rate constant2 (4) The photocatalytic activity of tin sulphide catalysts on the dyes can be fitted well in pseudofirst order kinetics using Eq. 4, where the apparent reaction rate constant (kap) for degradation can be found out.
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Figure S1. Optical absorption spectrum, tauc’s plot and nanoparticle dispersion in ethanol for (a) SnS2 NDs and (b) GSnS2 NDs composite, respectively.
Figure S2. Scanning electron microscopy, (a and b) are SEM images and (c and d) are EDAX spectra of SnS2 NFs and GSnS2 nanomaterials respectively.
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Figure S3. (a) Low magnification TEM image of GSnS2 ND composite synthesized at 15 h of reaction time. (b) TEM image of controlled reaction product, reaction parameters are similar to nanodiscs formation reaction except this reaction was carried out for 5 h. (c) Powder XRD patterns of GSnS2 NDs at different reaction time as indicated along with bulk SnS2 XRD pattern. * is the impurity phase.
Figure S4. Optical absorption spectrum (in ethanol) and tauc’s plot (inset) of SnS2 NSs.
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Figure S5. Comparison of photocatalytic activity of GSnS2 NDs with varying amount of GO on Rh B degradation reaction.
Figure S6. Post characterizations of catalyst and byproduct. (a) Chromatogram (HPLC) of pure MB before photocatalysis and reaction mixture after photocatalytic degradation using GSnS2 NDs. (b) Optical absorption spectra of MB dye before photocatalysis and reaction mixture after completion of photocatalytic reaction.
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Figure S7: Recyclability test for 50 cycles of photocatalysis (Rh B degradation to check the durability of photocatalyst GSnS2 NDs). Post characterization of GSnS2 NDs after 50 cycles of photocatalysis (a) XRD and (b) TEM image.
Figure S8. Recyclability test for Cr (VI) photo reduction using GSnS2 and SnS2 photocatalyst.
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Figure S9. TEM image of GSnS2 NFs photocatalyst after completion of Cr (VI) reduction.
References: 1. Chauhan. H.; Singh. M.K.; Hashmi. S. A.; Deka. S.; Synthesis of surfactant-free SnS nanorods by a solvothermal route with better electrochemical properties towards supercapacitor applications. RSC Adv., 2015, 5, 17228–17235. 2. Kush. P.; Deori K.; Kumar. A.; Deka. S.; Efficient hydrogen/oxygen evolution and photocatalytic dye degradation and reduction of aqueous Cr(VI) by surfactant free hydrophilic Cu2ZnSnS4 nanoparticles. J. Mater. Chem. A, 2015, 3,809
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Tandem photocatalysis of graphene stacked SnS2 nanodiscs and nanosheets with efficient carrier separation Himani Chauhan, Kiran Soni, Mukesh Kumar and Sasanka Deka* Department of Chemistry, University of Delhi, North campus, Delhi-110007, India Fax: (+) 91-11-27667206, E-mail: [email protected], [email protected]
Equations used for band gap determination1 (h)n = A*(h − Eg)
(1)
where h is the photon energy, n is an index characterizing the type of optical transition, A* is a certain frequency independent constant, Eg is optical band gap and is absorption coefficient defined by Beer-Lambert law as follows
= −lnA/l
(2)
Where l is optical path length and A is absorbance. Optical band gap and the nature of transition are determined by ploting (Ah) n vs. hv, where n = 2 for direct transition. Equations used for dye degradation percentage2 D
(3)
Where Ao is the initial absorbance at adsorption-desorption equilibrium before the addition of the catalyst and At is the absorbance of remnant dye at definite intervals of time‘t’ after the addition of the photocatalyst. Equations used for apparent rate constant2 (4) The photocatalytic activity of tin sulphide catalysts on the dyes can be fitted well in pseudofirst order kinetics using Eq. 4, where the apparent reaction rate constant (kap) for degradation can be found out.
S1
Figure S1. Optical absorption spectrum, tauc’s plot and nanoparticle dispersion in ethanol for (a) SnS2 NDs and (b) GSnS2 NDs composite, respectively.
Figure S2. Scanning electron microscopy, (a and b) are SEM images and (c and d) are EDAX spectra of SnS2 NFs and GSnS2 nanomaterials respectively.
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Figure S3. (a) Low magnification TEM image of GSnS2 ND composite synthesized at 15 h of reaction time. (b) TEM image of controlled reaction product, reaction parameters are similar to nanodiscs formation reaction except this reaction was carried out for 5 h. (c) Powder XRD patterns of GSnS2 NDs at different reaction time as indicated along with bulk SnS2 XRD pattern. * is the impurity phase.
Figure S4. Optical absorption spectrum (in ethanol) and tauc’s plot (inset) of SnS2 NSs.
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Figure S5. Comparison of photocatalytic activity of GSnS2 NDs with varying amount of GO on Rh B degradation reaction.
Figure S6. Post characterizations of catalyst and byproduct. (a) Chromatogram (HPLC) of pure MB before photocatalysis and reaction mixture after photocatalytic degradation using GSnS2 NDs. (b) Optical absorption spectra of MB dye before photocatalysis and reaction mixture after completion of photocatalytic reaction.
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Figure S7: Recyclability test for 50 cycles of photocatalysis (Rh B degradation to check the durability of photocatalyst GSnS2 NDs). Post characterization of GSnS2 NDs after 50 cycles of photocatalysis (a) XRD and (b) TEM image.
Figure S8. Recyclability test for Cr (VI) photo reduction using GSnS2 and SnS2 photocatalyst.
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Figure S9. TEM image of GSnS2 NFs photocatalyst after completion of Cr (VI) reduction.
References: 1. Chauhan. H.; Singh. M.K.; Hashmi. S. A.; Deka. S.; Synthesis of surfactant-free SnS nanorods by a solvothermal route with better electrochemical properties towards supercapacitor applications. RSC Adv., 2015, 5, 17228–17235. 2. Kush. P.; Deori K.; Kumar. A.; Deka. S.; Efficient hydrogen/oxygen evolution and photocatalytic dye degradation and reduction of aqueous Cr(VI) by surfactant free hydrophilic Cu2ZnSnS4 nanoparticles. J. Mater. Chem. A, 2015, 3,809
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