Photochemical Reduction of CO 2 by Graphitic Carbon Nitride Polymers

Transcription

1 Supporting Information Photochemical Reduction of CO 2 by Graphitic Carbon Nitride Polymers Jinliang Lin, Zhiming Pan, and Xinchen Wang* Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou, , P.R. China * To whom correspondence should be addressed. Address: xcwang@fzu.edu.cn Experimental materials: All the reagents used are analysis grades without further purification. 2,2`-bipyridine(bpy, Sigma), CoCl 2 (Sigma), MnCl 2 (Sigma), FeCl 2 (Sigma), RuCl 2 (Sigma), PdCl 2 (Sigma), CdCl 2 (Sigma), NiCl 2 (Sigma), CuCl 2 (Sigma), Cobaltocene (CP 2 Co, Sigma), tetramethylsilane (TMS, Alfa, analytic pure)were used as received. The organic solvents, including N,N-dimethylformamide (DMF, anhydrous,99.8%), Tetrahydrofufan (THF, anhydrous,99.9%), Acetonitrile (MeCN, anhydrous, 99.8%), and Trichloromethane (TCM, anhydrous, 99%) are purchased from China Sinopharm Chemical reagent Co. Ltd. and stored over molecular sieve, which used directly without further purification. S 1

2 Figure S1. 13 C NMR spectra in various conditions after reaction (under N 2 with light irradiation, under 13 CO 2 without light irradiation, under 13 CO 2 with light irradiation). Inset: 13 C NMR spectra of solution in ppm region, Peaks were referenced to TMS. S 2

3 Figure S2. The evolution of H 2 and CO as function of the amount of CoCl 2 in the presence of bpy (curve 1 &2 ) and in the absence of bpy (curve 3&4). S 3

4 Figure S3. Photoluminescence spectra of the samples dispersed in acetonitrile. All these suspensions containing carbon nitride were excited by 400 nm light, and exhibit identical emission spectrum with a broad emission band from 350 to 600 nm at room temperature. The spectra were originated by the electron-hole recombination. The decreasing intensities revealed the synergistic effect on charge separation in the presence of both CoCl 2 and bpy. ref1 S 4

5 Figure S4. The XRD patterns for fresh and used graphitic carbon nitride catalysts. The strongest XRD peak at 27.3 o is a characteristic inter-layer stacking reflection of conjugated aromatic systems and stacking distance of the aromatic units of d=0.326 nm can be calculated. The peak at 13.1 o represents the intralayer periodicity and the distance of in-planar repeating units is nm. ref2 S 5

6 Figure S5. The FT-IR patterns of fresh and used graphitic carbon nitride. The intense bands arranged from 1640 to 1412 cm -1 were assigned to typical stretching vibration modes of heptazine-derived repeating units. The intense band at 812 cm -1 corresponded to the out-of-plane bending vibration characteristic of heptazine rings. The broad weak band around 3236 cm-1 represented residual N-H components and O-H band assignable to uncondensed amino groups and adsorbed H 2 O molecules, respectively. ref2 S 6

7 Figure S6. Nitrogen adsorption-desorption isotherms and the corresponding Barrett-Joyner-Halenda (BJH) pore-size distribution curve of MCN. The pore-size distribution was determined from the desorption branch of the isotherms. S 7

8 Table S1. The effect of different metal ions on the CO 2 photoreduction. Entry M n+[b] CO /µmol H 2 /µmol CO+H 2 /µmol Sel./% [c] 1 Fe Cu 2+ n.d.[d] / 3 Mn Cd 2+ n.d. <0.1 <0.1 / 5 Ni [a] Reaction conditions: The same as those Table 1. [b] Metal cation. [c] Selectivity=n CO /n (CO+H2) 100. [d] No detected. S 8

9 Table S2. The photocatalytic activities of the system using different solvents [a]. Entry Solvent CO /µmol H 2 /µmol CO+H 2 /µmol Sel./% [b] 1 Water Acetonitrile N,N-Dimethyl formamide Trichloromethane 0.4 < / 5 Tetrahydrofuran [a] Reaction conditions: The same as Table 1. [b] Selectivity=n CO /n (CO+H2) 100. References: ref 1: Thomas, A.; Fischer, A.; Goettmann, F.; Antonietti, M.; Muller, J. O.; Schlogl, R.; Carlsson, J. M. J. Mater. Chem. 2008, 18, ref 2: Wang, X. C.; Maeda, K.; Thomas, A.; Takanabe, K.; Xin,G.; Carlsson, J. M.; Domen, K.; Antonietti, M. Nat. Mater. 2009, 8, 76. ref 3: Gold, J.; Amandusson, H.; Krozer, A.; Kasemo, B.; Ericsson, T.; Zanetti, G.; Fubini, B. Enviro. Health Persp. 1997, 105, S 9