Direct water splitting under visible light with nanostructured hematite and WO3 photoanodes and a GaInP2 photocathode
Direct water splitting under visible light with nanostructured hematite and WO3 photoanodes and a GaInP2 photocathode
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DOI：
10.1149/1.2888477
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发表时间：
2008-01-01
影响因子：
3.9
通讯作者：
Turner, John A.
中科院分区：
文献类型：
--
作者：
Wang, Heli;Deutsch, Todd;Turner, John A.
将p-GaInP 2光电阴极与纳米结构的赤铁矿和三氧化钨光电阳极配对，以研究这些系统在可见光照射下用于直接水分解的效用。对于赤铁矿系统，在开路条件下的照明下，赤铁矿的电位向阴极移动，而GaInP 2向阳极移动。在短路条件和可见光照射下，两个光电极的组合可以分解水，尽管即使在1 W/cm（2）的强度下也只有几μ A/cm（2）的非常低的速率。确定来自赤铁矿纳米棒光电极的非常低的光电流限制了双光电极组合的短路电流。观察到类似的电位偏移与纳米结构的WO 3/GaInP 2组合。然而，在低于0.2W/cm（2）的光强度下，由于电势差不足，短路的组合将不会分裂水。高于0.2 W/cm（2）时，该化合物可以在可见光下分解水，在1 W/cm（2）时获得类似于20 μ A/cm（2）。观察到的线性光电流-光强度的关系，并归因于有效的电荷转移和低复合的电荷载流子。WO 3的带隙和相关的吸收极限对于更高效率的系统仍然是一个挑战。(C)2008年电化学学会。
A p-GaInP2 photocathode was paired with nanostructured hematite and tungsten trioxide photoanodes to investigate the utility of these systems for direct water splitting under visible light illumination. For the hematite system, under illumination at open-circuit conditions, the potential of hematite shifts cathodically and that of the GaInP2 shifts anodically. Under short-circuit condition and visible light illumination, the combination of the two photoelectrodes can split water, though with a very low rate of a few mu A/cm(2) even at an intensity of 1 W/cm(2). It was determined that the very low photocurrent from the hematite nanorod photoelectrode limits the short-circuit current of the two-photoelectrode combination. Similar potential shifts were observed with the nanostructured WO3/GaInP2 combination. However, at light intensities below 0.2 W/cm(2), the short-circuited combination would not split water due to an insufficient potential difference. Above 0.2 W/cm(2), the combination can split water under visible light, with similar to 20 mu A/cm(2) obtained at 1 W/cm(2). A linear photocurrent-light intensity relationship was observed and was attributed to efficient charge transfer and a low recombination of the charge carriers. The bandgap and the associated absorption limit of WO3 remain a challenge for a higher efficiency system. (C) 2008 The Electrochemical Society.