Catalyst Deposition on Photoanodes: The Roles of Intrinsic Catalytic Activity, Catalyst Electrical Conductivity, and Semiconductor Morphology
Catalyst Deposition on Photoanodes: The Roles of Intrinsic Catalytic Activity, Catalyst Electrical Conductivity, and Semiconductor Morphology
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DOI：
10.1021/acsenergylett.8b00336
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发表时间：
2018-04-01
影响因子：
22
通讯作者：
Boettcher, Shannon W.
中科院分区：
文献类型：
--
作者：
Qiu, Jingjing;Hajibabaei, Hamed;Boettcher, Shannon W.
半导体氧化物光阳极用于驱动水分解系统中的析氧反应（OER）。性能最高的系统使用涂有水氧化催化剂的纳米结构半导体。尽管做了很多工作，但控制催化剂与半导体集成的设计原则却知之甚少。使用赤铁矿作为模型系统，我们展示了催化剂的半导体形态和电导率如何影响系统的光响应。导电催化剂如果同时接触半导体表面和下面的导电玻璃基板，就会引入大量的“分流”复合电流，从而导致性能不佳。通过使用无针孔半导体，在半导体表面使用选择性光辅助电沉积薄催化剂层，使用电绝缘催化剂层，或添加中间绝缘氧化层，可以在很大程度上消除这种复合。本研究的结果用于澄清文献中报道的几个重要结果背后的机制。
Semiconducting oxide photoanodes are used to drive the oxygen evolution reaction (OER) in water-splitting systems. The highest-performing systems use nanostructured semiconductors coated with water-oxidation catalysts. Despite much work, the design principles governing the integration of catalysts with semiconductors are poorly understood. Using hematite as a model system, we show how semiconductor morphology and electrical conductivity of the catalyst affect the system photoresponse. Electrically conductive catalysts can introduce substantial "shunt" recombination currents if they contact both the semiconductor surface and the underlying conducting-glass substrate, leading to poor performance. This recombination can be largely eliminated by using pinhole-free semiconductors, using selective photoassisted electrodeposition of thin catalyst layers on the semiconductor surface, using electrically insulating catalyst layers, or adding an intermediate insulating oxide layer. The results of this study are used to clarify the mechanisms behind several important results reported in the literature.