Characterization and Mechanism of Efficient Visible-Light-Driven Water Oxidation on an in Situ N2-Intercalated WO3 Nanorod Photoanode

被引：17

作者：

Chandra, Debraj ^{[1
,3
]}

Li, Dong ^{[1
]}

Sato, Tetsuya ^{[1
]}

Tanahashi, Yuki ^{[1
]}

Togashi, Takanari ^{[2
]}

Ishizaki, Manabu ^{[2
]}

Kurihara, Masato ^{[2
]}

Mohamed, Eman A. ^{[1
]}

Tsubonouchi, Yuta ^{[1
]}

Zahran, Zaki N. ^{[1
]}

Saito, Kenji ^{[1
]}

Yui, Tatsuto ^{[1
]}

Yagi, Masayuki ^{[1
]}

机构：

[1] Niigata Univ, Dept Mat Sci & Technol, Fac Engn, 8050 Ikarashi 2, Niigata 9502181, Japan

[2] Yamagata Univ, Fac Sci, 1-4-12 Kojirakawa Machi, Yamagata 9908560, Japan

[3] Tokyo Inst Technol, Inst Innovat Res, WRHI, Midori Ku, Nagatsuta Cho 4259, Yokohama, Kanagawa 2268503, Japan

来源：

ACS SUSTAINABLE CHEMISTRY & ENGINEERING | 2019年 / 7卷 / 21期

关键词：

water oxidation; tungsten trioxide; photoelectrocatalysis; water splitting; nanomaterials; OXYNITRIDE TAON PHOTOANODE; TUNGSTEN TRIOXIDE; PHOTOCATALYTIC ACTIVITY; PHOTOELECTROCHEMICAL PROPERTIES; FILM ELECTRODES; ARRAYS; OXIDE; PERFORMANCE; FABRICATION; FACILE;

D O I：

10.1021/acssuschemeng.9b04467

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Nanorod architecture of a N-2-intercalated WO3 photoanode has been developed by emphasizing the dual role of N2H4, which functioned simultaneously as a structure-directing agent and as a nitrogen source for in situ N-2 intercalation. The N content for WO3-N2H4 increased with increase of calcination temperature from 350 to 420 degrees C and thereafter decreased up to 550 degrees C. This is different from the monotonously decreased N content with the calcination temperature increase for WO3-NH3. X-ray diffraction data indicated that the phase-pure monoclinic WO3 crystals are formed over 350 degrees C calcination for WO3-N2H4, in contrast to a mixed phase of hexagonal and monoclinic WO3 crystals below 500 degrees C for WO3-NH3. The crystallinity of the monoclinic phase for WO3-N2H4 is higher than those of WO3-neat and WO3-NH3 at each calcination temperature of 350-550 degrees C. The beta values of lattice parameters of the monoclinic phase changed significantly with the calcination temperature; this is consistent with the calcination temperature dependence of the N content, clarifying the intercalation of N-2 in the WO3 lattice. The UV-visible diffuse reflectance spectra of WO3-N2H4 exhibited a shoulder at 470-630 nm, which became more intense as the calcination temperature increased from 350 degrees C and then decreased up to 550 degrees C through the maximum at 420 degrees C. This temperature dependence is consistent with the cases of the N content and the lattice parameter of beta. This indicates that N-2 intercalation into the WO3 lattice is responsible for the considerable red shift in the absorption edge, with a new shoulder appearing at 470-630 nm due to transition from a new intermediate N 2p orbital formed in the conduction band of WO3. Based on this transition, the WO3-N2H4 photoanode can utilize the visible light in longer wavelength below 520 nm for photoelectrochemical water oxidation compared to 470 nm for WO3-neat. The high incident photon-to-current conversion efficiency of the WO3-N2H4 photoanode is due to efficient electron transport through the WO3 nanorod film.

引用

页码：17896 / 17906

页数：21

共 77 条

[1] Facile Fabrication of an Efficient Oxynitride TaON Photoanode for Overall Water Splitting into H2 and O2 under Visible Light Irradiation [J].