Статья

Hydrogen-Treated TiO<sub>2</sub> Nanowire Arrays for Photoelectrochemical Water Splitting

Gongming WangDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United StatesHanyu WangDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United StatesYichuan LingDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United StatesYuechao TangKey Laboratory of Molecular Engineering of Polymer (Minister of Education), Department of Macromolecular Science and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, People’s Republic of ChinaXunyu YangDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United StatesRobert C. FitzmorrisDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United StatesChangchun WangKey Laboratory of Molecular Engineering of Polymer (Minister of Education), Department of Macromolecular Science and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, People’s Republic of ChinaJin Z. ZhangDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United StatesYat LiDepartment of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064 United States

2011en

ABI

Аннотация

We report the first demonstration of hydrogen treatment as a simple and effective strategy to fundamentally improve the performance of TiO(2) nanowires for photoelectrochemical (PEC) water splitting. Hydrogen-treated rutile TiO(2) (H:TiO(2)) nanowires were prepared by annealing the pristine TiO(2) nanowires in hydrogen atmosphere at various temperatures in a range of 200-550 °C. In comparison to pristine TiO(2) nanowires, H:TiO(2) samples show substantially enhanced photocurrent in the entire potential window. More importantly, H:TiO(2) samples have exceptionally low photocurrent saturation potentials of -0.6 V vs Ag/AgCl (0.4 V vs RHE), indicating very efficient charge separation and transportation. The optimized H:TiO(2) nanowire sample yields a photocurrent density of ∼1.97 mA/cm(2) at -0.6 V vs Ag/AgCl, in 1 M NaOH solution under the illumination of simulated solar light (100 mW/cm(2) from 150 W xenon lamp coupled with an AM 1.5G filter). This photocurrent density corresponds to a solar-to-hydrogen (STH) efficiency of ∼1.63%. After eliminating the discrepancy between the irradiance of the xenon lamp and solar light, by integrating the incident-photon-to-current-conversion efficiency (IPCE) spectrum of the H:TiO(2) nanowire sample with a standard AM 1.5G solar spectrum, the STH efficiency is calculated to be ∼1.1%, which is the best value for a TiO(2) photoanode. IPCE analyses confirm the photocurrent enhancement is mainly due to the improved photoactivity of TiO(2) in the UV region. Hydrogen treatment increases the donor density of TiO(2) nanowires by 3 orders of magnitudes, via creating a high density of oxygen vacancies that serve as electron donors. Similar enhancements in photocurrent were also observed in anatase H:TiO(2) nanotubes. The capability of making highly photoactive H:TiO(2) nanowires and nanotubes opens up new opportunities in various areas, including PEC water splitting, dye-sensitized solar cells, and photocatalysis.

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Идентификаторы

DOI: 10.1021/nl201766h

Цитирования и источники

Цитирований: 2Использованных источников: 0

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