Amorphous TiO2 coatings stabilize Si, GaAs, and GaP photoanodes for efficient water oxidation
Amorphous TiO2 coatings stabilize Si, GaAs, and GaP photoanodes for efficient water oxidation
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DOI：
10.1126/science.1251428
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发表时间：
2014-05-30
期刊：
影响因子：
56.9
通讯作者：
Lewis, Nathan S.
中科院分区：
文献类型：
--
作者：
Hu, Shu;Shaner, Matthew R.;Lewis, Nathan S.
尽管硅(Si)、砷化镓(GaP)和磷化镓(GaP)等半导体材料具有带隙，使它们成为生产太阳能燃料的高效光阳极，但这些材料在水介质中不稳定。我们发现，通过原子层沉积生长的二氧化钛涂层(4到143纳米厚)可以防止腐蚀，具有促进空穴导电的电子缺陷，并且足够透明，可以达到受保护半导体的光限幅性能。结合薄层或岛状的镍氧化物电催化剂，硅光阳极在光电流密度为30毫安/平方厘米、接近100%法拉第效率的情况下，连续氧化1.0摩尔的KOH为O-2超过100小时。对于水氧化，TiO2光电极的光电压分别为0.81和0.59V，光电流密度分别为14.3和3.4毫安/平方厘米。
Although semiconductors such as silicon (Si), gallium arsenide (GaAs), and gallium phosphide (GaP) have band gaps that make them efficient photoanodes for solar fuel production, these materials are unstable in aqueous media. We show that TiO2 coatings (4 to 143 nanometers thick) grown by atomic layer deposition prevent corrosion, have electronic defects that promote hole conduction, and are sufficiently transparent to reach the light-limited performance of protected semiconductors. In conjunction with a thin layer or islands of Ni oxide electrocatalysts, Si photoanodes exhibited continuous oxidation of 1.0 molar aqueous KOH to O-2 for more than 100 hours at photocurrent densities of >30 milliamperes per square centimeter and similar to 100% Faradaic efficiency. TiO2-coated GaAs and GaP photoelectrodes exhibited photovoltages of 0.81 and 0.59 V and light-limiting photocurrent densities of 14.3 and 3.4 milliamperes per square centimeter, respectively, for water oxidation.