Oxygen-deficient WO3−x nanoplate array film photoanode for efficient photoelectrocatalytic water decontamination
Oxygen-deficient WO3−x nanoplate array film photoanode for efficient photoelectrocatalytic water decontamination
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DOI：
10.1016/j.cej.2019.122740
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发表时间：
2020-02
影响因子：
15.1
通讯作者：
X. Liu;Hao Zhou;Shuzhao Pei;S. Xie;S. You
中科院分区：
文献类型：
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作者：
X. Liu;Hao Zhou;Shuzhao Pei;S. Xie;S. You
光电催化（PEC）是一种很有前途的水净化方法，但其整体性能受到界面电荷转移缓慢的限制。在这项研究中，我们通过表面还原方法，用缺氧WO3−x纳米板阵列薄膜作为光阳极，创建了一个高效的PEC系统，解决了这一限制。氧空位对光阳极的催化活性影响较小，但当阳极极化时，氧空位对光阳极的催化活性有增强作用。基于正面照明和1.2 V vs标准氢电极（SHE）的电位，WO3−x光阳极产生的光电流是WO3光阳极的7.3倍，表明界面电荷转移大大增强。在单独的光催化条件下，WO3和WO3−x电极对4-氯酚（4-CP）的去除率和脱氯效果均不显著。在1.2 V vs SHE的阳极极化条件下，WO3−x光阳极的4-氯酚去除率为85.5%，脱氯效率为48%，分别比WO3光阳极高32.7%和25.8%。WO3−x（k= 0.0157 min−1）去除4-CP的一级动力学常数约为WO3（k= 0.0062 min−1）的2.53倍。低电位偏压下WO3−x光阳极PEC性能的提高可能是由于界面电荷转移速度加快，电子-空穴复合减少，羟基自由基（dotOH）的生成量增加。该研究不仅表明了氧空位在PEC系统中的重要作用，而且为开发全太阳能水净化系统提供了新的策略。
Photoelectrocatalysis (PEC) represents a promising method for water decontamination, but the overall performance is limited by slow interfacial charge transfer. In this study, we address this limitation by creating an efficient PEC system with oxygen-deficient WO3−xnanoplate array film serving as photoanode through surface reduction method. Oxygen vacancy had a slight impact to catalytic activity of photoanode, but exhibited an enhanced performance when anodic polarization was imposed. Based on a front-side illumination and potential of 1.2 V vs standard hydrogen electrode (SHE), the WO3−xphotoanode produced a photocurrent being 7.3 times as WO3photoanode, indicating a substantially enhanced interfacial charge transfer. Both WO3and WO3−xelectrodes showed an insignificant removal of 4-chlorophenol (4-CP) and dechlorination under individual photocatalytic condition. When anodic polarization was applied at 1.2 V vs SHE, 85.5% removal of 4-chlorophenol (4-CP) and 48% dechlorination efficiency could be obtained for WO3−xphotoanode, accounting for the values being 32.7% and 25.8% higher than that for WO3photoanode. The corresponding first-order kinetic constant for 4-CP removal by WO3−x(k= 0.0157 min−1) was approximately 2.53 times as that by WO3(k= 0.0062 min−1). The improved PEC performance of WO3−xphotoanode under low potential bias should result from faster interfacial charge transfer, mitigation of electron-hole recombination, and production of higher amount of hydroxyl radical (radical dotOH). This study not only suggests the important role of oxygen vacancy in PEC system, but also provides a new strategy to develop a full solar-energy-based water purification system.