H:ZnO Nanorod-Based Photoanode Sensitized by CdS and Carbon Quantum Dots for Photoelectrochemical Water Splitting

详细信息    查看全文

• 作者：Nguyen Minh Vuong ; John Logan Reynolds ; Eric Conte ; Yong-Ill Lee
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：October 29, 2015
• 年：2015
• 卷：119
• 期：43
• 页码：24323-24331
• 全文大小：498K
• ISSN：1932-7455

文摘

We report a promising simple strategy for improving the performance of the photoanode for photoelectrochemical (PEC) water splitting. ZnO nanorods on an indium tin oxide glass substrate were synthesized by a hydrothermal method following calcinations in air at 500 掳C for 2 h and pure ambient hydrogen at atmospheric pressure at 400 掳C for 30 min. The hydrogenated ZnO (H:ZnO) sample shows an enhanced photocurrent in comparison to that of ZnO nanorods. To enhance the absorption in the visible light and near-infrared regions, H:ZnO nanorods were sensitized by cadmium sulfide (CdS) nanoparticles and carbon quantum dots (CQDs). The H:ZnO nanorod film sensitized in this way exhibited significantly improved PEC properties after treatment with ambient nitrogen at 400 掳C for 30 min. The optimized H:ZnO nanorod sample sensitized by CdS and CQDs yields a photocurrent density of 鈭?2.82 mA/cm² at 0 V (vs saturated calomel electrode (SCE)) in 0.25 M Na₂S and 0.35 M Na₂SO₃ solution under the illumination of simulated solar light (100 mW/cm² from a 150 W xenon Arc lamp source). The optimal structure shows a solar-to-hydrogen conversion efficiency of 鈭?.85% (at 鈭?.67 V vs SCE). The H₂ gas generation obtained using this optimal structure consisting of H:ZnO nanorods sensitized by CdS and CQDs was 7.04 mL/cm² in 1 h. The morphology and properties of the samples were examined by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, ultraviolet鈥搗isible absorption, and electrical measurements.