Synthesis of Nanostructured BaTaO2N Thin Films as Photoanodes for ...
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Synthesis of Nanostructured BaTaO2N Thin Films as Photoanodes for Solar Water Splitting Chizhong Wang,1 Takashi Hisatomi,1,2 Tsutomu Minegishi,1,2,3 Qian Wang,1,2 Miao Zhong,1,2 Masao Katayama,1,2 Jun Kubota1,† and Kazunari Domen1,2, 1
Department of Chemical System Engineering, School of Engineering, The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan 2
Japan Technological Research Association of Artificial Photosynthetic Chemical Process
(ARPChem), 5-1-5 Kashiwanoha, Kashiwa-shi, 277-8589 Chiba, Japan 3
Japan Science and Technology Agency / Precursory Research for Embryonic Science and
Technology (JST/PRESTO), Kawaguchi Center Building, 4-1-8, Honcho, Kawaguchi-shi, 332-0012 Saitama, Japan †
Current Affiliation: Department of Chemical Engineering, Fukuoka University 8-19-1 Nanakuma,
Jonan-ku, 814-0180 Fukuoka, Japan
Corresponding author. Fax: +81 3 5841 8838; Tel: +81 3 5841 1148.
E-mail: [email protected] (K. Domen).
Figure S1. (a) XRD patterns for Ba5Ta4O15 prepared by a hydrothermal reaction, and the reference pattern (PDF# 18-0193). (b) Stereoscopic views of Ba5Ta4O15 and BaTaO2N unit cells. Large green and small blue spheres represent Ba and O atoms, respectively, and grey spheres at the center of octahedra indicate Ta atoms. In the BaTaO2N unit cell, mixed color spheres represent O and N atoms (blue for O atoms and red for N atoms). All the cell structures were depicted using the VESTA software based on standard XRD reference cards in the ICSD database. (c) Schematic illustration of the vertical growth of a Ba5Ta4O15 nanosheet on a Ta substrate during the hydrothermal reaction. In the presence of a high concentration of OH- ions, horizontal growth of Ba5Ta4O15 crystallites along the direction is evidently inhibited.
Figure S2. XRD patterns for BaTaO2N films nitrided at 1000 °C for 2 h with NH3 gas flow rates of 10 and 100 sccm.
Figure S3. Current-potential curves for bare BaTaO2N photoanodes prepared at nitriding temperatures of 850, 900, 950, and 1000 °C. All the electrodes were measured in a 0.5 M potassium phosphate solution (pH = 13) under simulated AM 1.5G light.
Figure S4. (a) Ba 3d and (b) O 1s XPS spectra for Ba5Ta4O15 and BaTaO2N films, and a CoPi/BaTaO2N photoelectrode after measurement for 5 h at 1.23 V vs. RHE in a 0.5 M potassium phosphate solution (pH = 13) under simulated AM 1.5G light.
Figure S5. Photon flux spectra for standard AM 1.5G (ASTM G173-03) and the solar simulator used for the PEC measurements. The red curve depicts the photocurrent density calculated based on the solar simulator spectrum and the IPCE curve shown in Figure 5(c) in the main text. The total photon flux (350660 nm) of the solar simulator and the standard AM 1.5G spectra are 9.96×1020 and 1.07×1021 photons m-2 s-1, giving an integrated photocurrent density of 0.58 and 0.62 mA cm-2, respectively.
Synthesis of Nanostructured BaTaO2N Thin Films as Photoanodes for Solar Water Splitting Chizhong Wang,1 Takashi Hisatomi,1,2 Tsutomu Minegishi,1,2,3 Qian Wang,1,2 Miao Zhong,1,2 Masao Katayama,1,2 Jun Kubota1,† and Kazunari Domen1,2, 1
Department of Chemical System Engineering, School of Engineering, The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan 2
Japan Technological Research Association of Artificial Photosynthetic Chemical Process
(ARPChem), 5-1-5 Kashiwanoha, Kashiwa-shi, 277-8589 Chiba, Japan 3
Japan Science and Technology Agency / Precursory Research for Embryonic Science and
Technology (JST/PRESTO), Kawaguchi Center Building, 4-1-8, Honcho, Kawaguchi-shi, 332-0012 Saitama, Japan †
Current Affiliation: Department of Chemical Engineering, Fukuoka University 8-19-1 Nanakuma,
Jonan-ku, 814-0180 Fukuoka, Japan
Corresponding author. Fax: +81 3 5841 8838; Tel: +81 3 5841 1148.
E-mail: [email protected] (K. Domen).
Figure S1. (a) XRD patterns for Ba5Ta4O15 prepared by a hydrothermal reaction, and the reference pattern (PDF# 18-0193). (b) Stereoscopic views of Ba5Ta4O15 and BaTaO2N unit cells. Large green and small blue spheres represent Ba and O atoms, respectively, and grey spheres at the center of octahedra indicate Ta atoms. In the BaTaO2N unit cell, mixed color spheres represent O and N atoms (blue for O atoms and red for N atoms). All the cell structures were depicted using the VESTA software based on standard XRD reference cards in the ICSD database. (c) Schematic illustration of the vertical growth of a Ba5Ta4O15 nanosheet on a Ta substrate during the hydrothermal reaction. In the presence of a high concentration of OH- ions, horizontal growth of Ba5Ta4O15 crystallites along the direction is evidently inhibited.
Figure S2. XRD patterns for BaTaO2N films nitrided at 1000 °C for 2 h with NH3 gas flow rates of 10 and 100 sccm.
Figure S3. Current-potential curves for bare BaTaO2N photoanodes prepared at nitriding temperatures of 850, 900, 950, and 1000 °C. All the electrodes were measured in a 0.5 M potassium phosphate solution (pH = 13) under simulated AM 1.5G light.
Figure S4. (a) Ba 3d and (b) O 1s XPS spectra for Ba5Ta4O15 and BaTaO2N films, and a CoPi/BaTaO2N photoelectrode after measurement for 5 h at 1.23 V vs. RHE in a 0.5 M potassium phosphate solution (pH = 13) under simulated AM 1.5G light.
Figure S5. Photon flux spectra for standard AM 1.5G (ASTM G173-03) and the solar simulator used for the PEC measurements. The red curve depicts the photocurrent density calculated based on the solar simulator spectrum and the IPCE curve shown in Figure 5(c) in the main text. The total photon flux (350660 nm) of the solar simulator and the standard AM 1.5G spectra are 9.96×1020 and 1.07×1021 photons m-2 s-1, giving an integrated photocurrent density of 0.58 and 0.62 mA cm-2, respectively.
