Enhanced photoelectrochemical water splitting with TiO2@Ag2O nanowire arrays via p-n heterojunction formation
Enhanced photoelectrochemical water splitting with TiO2@Ag2O nanowire arrays via p-n heterojunction formation
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通过 p-n 异质结形成 TiO2@Ag2O 纳米线阵列增强光电化学水分解
DOI：
10.1016/j.solmat.2017.08.033
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发表时间：
2018-01-01
影响因子：
6.9
通讯作者：
Shi, Honglong
中科院分区：
文献类型：
--
作者：
Hao, Chenchun;Wang, Wenzhong;Shi, Honglong
采用水热法和化学浴法相结合的方法制备了纳米TiO2@Ag2O p-n异质结阵列，并将其作为光电化学（PEC）电池的光电极用于高效太阳能水分解。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、X射线光电子能谱（XPS）和电化学阻抗谱（EIS）对原始TiO 2纳米线阵列（TiO 2 NWAs）和Ag 2 O纳米粒子修饰的TiO 2纳米线（TiO2@Ag2O NWAs）进行了表征。纳米TiO 2纳米线阵列与Ag 2 O纳米粒子组装在一起，形成了大量的纳米p-n异质结。在模拟AM 1.5照明（100 mW/cm（2））下，TiO2@Ag2O p-n异质结阵列在1.23 V下相对于0.5 M Na 2SO 4电解质中的可逆氢电极（FtHE）显示出1.61 mA/cm（2）的光电流密度，比原始TiO 2 NWA的光电流密度高两倍。这种增强归因于p-Ag 2 O和n-TiO 2之间的p-n异质结界面有效的电子-空穴分离，这通过包括有或无照明的Mott-Schottky和Nyquist图的电化学阻抗谱来揭示。TiO2@Ag2O p-n异质结阵列有望在太阳能水分解方面具有相当大的应用潜力。
Nanostructured TiO2@Ag2O p-n heterojunction arrays were fabricated by combining the hydrothermal method with the chemical-bath method, and they were used as a photoelectrode in photoelectrochemical (PEC) cell for high-performance solar water splitting. To investigate the morphology, microstructure and composition, the pristine TiO2 nanowire arrays (TiO2 NWAs) and the TiO2 nanowires decorated with Ag2O nanoparticles (TiO2@Ag2O NWAs) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectra (EIS). Nanostructured TiO2 nanowire arrays were assembled with Ag2O nanoparticles, producing a large number of nano p-n heterojunctions. The TiO2@Ag2O p-n heterojunction arrays showed a photocurrent density of 1.61 mA/cm(2) at 1.23 V vs. a reversible hydrogen electrode (FtHE) in 0.5 M Na2SO4 electrolyte under simulated AM 1.5 illumination (100 mW/cm(2)), two times higher than that of the pristine TiO2 NWAs. The enhancement was attributed to the efficient electron-hole separation because of the p-n heterojunction interface between p-Ag2O and n-TiO2, which were revealed by-the electrochemical impedance spectra including both Mott-Schottky and Nyquist plots with or without illumination. TiO2@Ag2O p-n heterojunction arrays were expected to have the considerably potential applications in solar water splitting.