Solar water oxidation by composite catalyst/alpha-Fe(2)O(3) photoanodes.
Solar water oxidation by composite catalyst/alpha-Fe(2)O(3) photoanodes.
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DOI：
10.1021/ja9016478
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发表时间：
2009-04
影响因子：
15
通讯作者：
Diane K. Zhong;Jianwei Sun;Hiroki Inumaru;D. Gamelin
中科院分区：
文献类型：
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作者：
Diane K. Zhong;Jianwei Sun;Hiroki Inumaru;D. Gamelin
在高表面积的α-Fe（2）O（3）光电阳极上电沉积无定形钴催化剂层，导致使用该阳极和模拟太阳照射的光电化学水氧化的起始电位中超过350 mV的阴极偏移。催化剂层被示出为共形地存款到介观结构的α-Fe（2）O（3）上，导致在复合光阳极的两个半部之间的界面处的大接触面积。光电化学测量表明，从这种复合光电阳极产生的光电流仍然来自于α-Fe（2）O（3）激发，但现在可以在低于单独的α-Fe（2）O（3）光电阳极通常所需的几百毫伏的外部偏压下获得，这表明需要降低的外部偏压来驱动整体水裂解。这些结果表明，用合格电催化剂的保形层对这种原型光阳极材料进行修饰，以分离光子吸收和氧化还原催化的任务，这一策略可能对太阳能光电化学制氢具有重要且普遍的影响。
Electrodeposition of an amorphous cobalt catalyst layer over a high-surface-area alpha-Fe(2)O(3) photoanode causes a more than 350 mV cathodic shift in the onset potential for photoelectrochemical water oxidation using this anode and simulated solar irradiation. The catalyst layer is shown to deposit conformally onto the mesostructured alpha-Fe(2)O(3), leading to a large contact area at the interface between the two halves of the composite photoanode. Photoelectrochemical measurements show that the photocurrent generated from this composite photoanode still derives from alpha-Fe(2)O(3) excitation but is now accessible at an external bias several hundred millivolts below what is typically required for alpha-Fe(2)O(3) photoanodes alone, indicating a reduced external bias would be needed to drive overall water splitting. These results demonstrate modification of this prototypical photoanode material with a conformal layer of a competent electrocatalyst to separate the tasks of photon absorption and redox catalysis, a strategy that may have important and general ramifications for solar photoelectrochemical hydrogen generation.