Efficient photoelectrochemical water splitting and impedance analysis of WO3¡x nanoflake electrodes
Efficient photoelectrochemical water splitting and impedance analysis of WO3¡x nanoflake electrodes
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WO3¡x 纳米片电极的高效光电化学水分解和阻抗分析
DOI：
10.1016/j.ijhydene.2017.01.177
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发表时间：
2017
影响因子：
7.2
通讯作者：
Z.J. Zhang
中科院分区：
文献类型：
--
作者：
S.Q. Yu;Y.H. Ling;J. Zhang;F. Qin;Z.J. Zhang
利用光电化学（PEC）装置进行太阳能水分解被认为是一种有前景的大规模同时收集和储存太阳能的方法。纳米结构半导体由于其较大的表面积和尺寸相关的特性，如增加的吸收系数、增加的带隙能量和降低的载流子散射率，在PEC应用中具有潜在的优势。本文采用Fe-W非晶合金脱合金、空气热处理和适当阴极极化的新工艺合成了自掺杂三氧化钨（WO3−x）纳米片阵列。研究了不同阴极极化电流导致不同WO3−x值对所得样品形貌、物相及光电化学性能的影响。结果表明，在适当的x值下，甲醇作为空穴清除剂存在时，WO3 - x纳米片的光电电流密度为8.7 mA cm - 2，是原始WO3纳米片的5倍。紫外-可见反射光谱表明，WO3−的光吸收光谱范围从紫外区延伸到可见光区。电化学阻抗谱揭示了独特的纳米片结构和表面缺陷提供了更好的光收集和有效的电荷传输。
Solar-powered water splitting with photoelectrochemical (PEC) devices is considered to be a promising method to simultaneously harvest and store solar energy at a large scale. Nanostructured semiconductors offer potential advantages in PEC application due to their large surface area and size-dependent properties, such as increased absorption coefficient, increased band-gap energy and reduced carrier-scattering rate. In this contribution, self-doped tungsten trioxide (WO3−x) nanoflake arrays were synthesized via a new route which involves the dealloying of Fe–W amorphous alloy, thermal treatment in air and properly cathodic polarization. The effects of different cathodic polarization current leading to different x value in WO3−xon the morphology, phase, and photoelectrochemical performance of the resultant samples were investigated. It was found that WO3−xwith the appropriate x value presents a dramatic photoelectrochemical current density of 8.7 mA cm−2in the presence of methanol as a hole scavenger, five folds larger than that of pristine WO3nanoflakes. UV–vis reflection spectra suggest that the light absorption spectrum range of WO3−xextends from UV to visible light region. Electrochemical impedance spectroscopy disclosed that the unique nanoflake architecture and the surface defects offer improved light harvesting as well as efficient charge transportation.