Dendritic Tip-on Polytriazine-Based Carbon Nitride Photocatalyst with High Hydrogen Evolution Activity

Transcription

1 Supplementary Information Dendritic Tip-on Polytriazine-Based Carbon Nitride Photocatalyst with High Hydrogen Evolution Activity Manas K. Bhunia, Sigismund Melissen, ǁ Manas R. Parida, Pradip Sarawade,, Jean-Marie Basset, Dalaver H. Anjum, Omar F. Mohammed, Philippe Sautet, ǁ Tangui Le Bahers ǁ and Kazuhiro Takanabe*, Division of Physical Sciences and Engineering, KAUST Catalysis Center (KCC), Solar and Photovoltaics Engineering Research Center, Imaging and Characterization Lab, King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal, Saudi Arabia. ǁ Université de Lyon, Université Claude Bernard Lyon 1, Centre National de Recherche Scientifique, Ecole Normale Supérieure Lyon, 46 allée d'italie, Lyon Cedex 07, France. Present Address: Department of Physics, University of Mumbai, Mumbai , India. 1

2 Experimental Section Synthesis of porous silica, KCC-1: KCC-1 was prepared following the reported procedure. S1 The KCC-1 powder (2 g) was mixed with concentrated HCl (12.1 N, 1.48 g) in 40 ml deionized water and kept in a static oven at 60 C in a static condition for 12 h. It was then centrifuged, and the solid product was dried at 80 C for overnight. Synthesis of g-c3n4: A porcelain crucible was loaded with melamine (Mel, 25 g) and covered with a porcelain lid. The crucible was placed in a muffle furnace (Nabertherm, L9/11/SKM), heated at 550 C for 4 h and then cooled to room temperature. The product was ground to a fine powder and represented as heptazine based g-c3n4. Synthesis of Polytriazine Imide (PTI): Mel (1.00 g, 7.93 mmol) and a eutectic mixture of LiCl (59.2 mol%, 2.26 g, mmol) and KCl (40.8 mol%, 2.74 g, mmol) were ground together. The reaction mixture was quickly transferred to a porcelain crucible covered with a lid, which was heated in a muffle furnace at a ramp of 12 C min 1 to 550 C. This temperature was maintained for 4 h, and the sample was then cooled to room temperature. The sample was ground to a powder and washed with boiling water to remove residual salts. The resulting material was a yellow powder and designated as PTI-0. Synthesis of Copolymerized Polytriazine Imide (PTI-X): Mel (1.00 g, 7.93 mmol) and the required amount of 2,4,6-triaminopyrimidine (TAP; X g) were added to 30 ml of absolute ethanol and stirred at 100 C for 2-3 h to achieve supramolecular aggregation. S2 Following the complete evaporation of the ethanol, a solid product was obtained. The following procedure is the same as PTI-0. The resulting brown powder was designated as PTI-X, where represents the mass ratio of TAP relative to Mel. Synthesis of Polytriazine Imide in the presence of KCC-1 (PTI-X/KCC-1): Mel (1.00 g, 7.93 mmol) with and without the required amount of TAP (X g), and KCC-1 (0.125 g) were added to 30 ml of absolute ethanol and stirred at 100 C for 2-3 h. The procedure is the same as that of the samples without KCC-1 (PTI-X). The resulting materials were designated as PTI-X/KCC-1, where X represents the mass ratio of TAP relative to Mel. Removal of silica: Polytriazine imides with KCC-1 (0.3 g of ) were mixed with 4 M NH4HF2 (Aldrich, 40 ml) solution, kept in a static condition overnight, filtered, and washed thoroughly with plenty of water. The solid products were then dried at 80 C for 5-6 h in an oven. 2

3 Figure S1. Measured photon flux for the range nm (left panel) and measured photon flux using band pass filters (right panel) using Asahi spectra Max-303 Xe lamp with UV-Vis mirror module. Table S1. Photocatalytic hydrogen evolution of, where precursor synthesis temperatures have been varied Sample BET SA (m 2 g 1 ) HER (µmol h 1 ) -RT C C C

4 Figure S2. TEM images of the KCC-1 as synthesized (a) and KCC-1 treated with a eutectic mixture of LiCl/KCl at 550 C for 4 h. Figure S3. Vibrational spectra (data recorded in the attenuated total reflectance mode) of PTI-0, PTI-0.15, and after silica removal. 4

5 (a) (b) (c) Figure S4. (a) Solid state single pulse 29 Si MAS NMR spectrum of KCC-1 and, (b) magnified spectrum of, (c) 13 C cross-polarization MAS NMR spectrum of, shown here. 5

6 (a) Wide (b) C 1s Si 2p O 1s N 1s C 1s (c) N 1s (d) O 1s (e) Si 2p Figure S5. XPS spectra of showing (a) survey spectrum, (b) carbon, (c) nitrogen, (d) oxygen and (e) silicon environments. 6

7 (a) Wide O 1s N 1s PTI-0.15 (b) C 1s PTI-0.15 C 1s (c) N 1s PTI-0.15 (d) O 1s PTI Figure S6. XPS spectra of PTI-0.15 showing (a) survey spectrum, (b) carbon, (c) nitrogen, and (d) oxygen environments. 7

8 (a) (b) Wide O 1s after silica removal N 1s C 1s C 1s PTI-0.15/ KCC-1 after silica removal (c) N 1s after silica removal (d) O 1s PTI-0.15/ KCC-1 after silica removal Figure S7. XPS spectra of PTI-0.15/ KCC-1 after silica removal showing (a) survey spectrum, (b) carbon, (c) nitrogen, and (d) oxygen environments. 8

9 (a) (b) Figure S8. (a) N2 isotherms and (b) Barrett-Joyner-Halenda (BJH) pore-size distribution from nitrogen adsorption/ desorption analysis. Calculations were based on the desorption analysis. Table S2. Surface area and pore-size analysis of synthesized carbon nitrides Sample Name Pore Size (nm) Pore Volume (cc g 1 ) BET SA (m 2 g 1 ) KCC / PTI silica removal

10 Figure S9. Transient absorption (TA) spectra of CN samples at indicated delay-time windows on the femtosecond time scale following laser pulse excitation at 350 nm. Table S3. Charge carrier lifetime measured with laser pulse excitation at 350 nm. Sample τ1 (ps) τ2 (ns) PTI ± ± ± ± 0.2 after silica removal 50 ± ± 0.3 The carrier trapping time constant was estimated using the two-exponential decay function: 1 exp (-t/τ1) + 2 exp (-t/τ2) Where, Ai and τi, i = 1 and 2 are the time independent coefficients and time constants determined by excitation fluence respectively. 10

11 Amount of evolved H 2 gas ( mol) TEOA added Time (h) Figure S10. Photocatalytic stability test of for 50 h, every 10 h evacuated, and 250 µl of TEOA was added after first 20 h. The deactivation was observed after 1 st run and then it showed stable activity. Figure S11. Powder XRD pattern of the sample after 15 h of photocatalytic reaction showing complete structural robustness. 11

12 Theoretical Section Here, both CIF and POSCAR formats are provided, POSCAR formats only are provided for the optimized monolayers. Band structures and Densities of States (DOSs) are provided for the 3D structures. CIF of optimized 3D-PTI-0 data_new_crystal _audit_creation_method _cell_length_a (0) _cell_length_b (0) _cell_length_c (0) _cell_angle_alpha (0) _cell_angle_beta (0) _cell_angle_gamma (0) _symmetry_space_group_name_h-m 'P 63/m c m' _symmetry_int_tables_number 193 _symmetry_cell_setting hexagonal loop symmetry_equiv_pos_as_xyz '+x,+y,+z' '-y,+x-y,+z' '-x+y,-x,+z' '-x,-y,1/2+z' '+y,-x+y,1/2+z' '+x-y,+x,1/2+z' '+y,+x,+z' '+x-y,-y,+z' '-x,-x+y,+z' '-y,-x,1/2+z' '-x+y,+y,1/2+z' '+x,+x-y,1/2+z' '-x,-y,-z' '+y,-x+y,-z' '+x-y,+x,-z' '+x,+y,1/2-z' '-y,+x-y,1/2-z' '-x+y,-x,1/2-z' '-y,-x,-z' '-x+y,+y,-z' '+x,+x-y,-z' '+y,+x,1/2-z' '+x-y,-y,1/2-z' '-x,-x+y,1/2-z' 'generated by CrystalMaker 8.7.4' loop atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z C1 C E E E-01 N1 N E E E-01 N2 N E E E-01 H1 H E E E-01 2D-PTI-0 0% C-doped, POSCAR 2D_gt_C6N9H3_based_on_ E E E E E E E E C N H Direct 12

13 E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E % C-doped, POSCAR 2D_gt_C6N9H3_12p5procent_doped E E E E E E E E C N H Direct E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E-4 13

14 E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E-3 50% C-doped, POSCAR 2D_gt_C6N9H3_50pC_doped E E E E E E E E C N H Direct E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E-04 2D_gt_C6N9H3_25pC_doped_repulsion E E E E E E E E C H N

15 Direct E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E-03 15

16 E E E E E E E E E E E E-05 Reference: S1. Polshettiwar, V.; Cha, D.; Zhang, X.; Basset, J. M. High-Surface-Area Silica Nanospheres (KCC-1) with a Fibrous Morphology. Angew. Chem. Int. Ed. 2010, 49, S2. Bhunia, M. K.; Yamauchi, K.; Takanabe, K. Harvesting Solar Light with Crystalline Carbon Nitrides for Efficient Photocatalytic Hydrogen Evolution. Angew. Chem. Int. Ed. 2014, 53,