Li Jingguo, Wan Wenchao, Triana C A, Novotny Zbynek, Osterwalder Jürg, Erni Rolf, Patzke Greta R
Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland.
Department of Physics , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland.
J Am Chem Soc. 2019 Aug 14;141(32):12839-12848. doi: 10.1021/jacs.9b06100. Epub 2019 Aug 2.
While loading of cocatalysts is one of the most widely investigated strategies to promote the efficiency of photoelectrodes, the understanding of their functionality remains controversial. We established new hybrid molecular photoanodes with cobalt-based molecular cubane cocatalysts on hematite as a model system. Photoelectrochemical and rate law analyses revealed an interesting functionality transition of the {Co(II)O}-type cocatalysts. Their role changed from predominant hole reservoirs to catalytic centers upon modulation of the applied bias. Kinetic analysis of the photoelectrochemical processes indicated that this observed transition arises from the dynamic equilibria of photogenerated surface charge carriers. Most importantly, we confirmed this functional transition of the cocatalysts and the related kinetic properties for several cobalt-based molecular and heterogeneous catalysts, indicating wide applicability of the derived trends. Additionally, complementary analytical characterizations show that a transformation of the applied molecular species occurs at higher applied bias, pointing to a dynamic interplay connecting molecular and heterogeneous catalysis. Our insights promote the essential understanding of efficient (molecular) cocatalyzed photoelectrode systems to design tailor-made hybrid devices for a wide range of catalytic applications.
虽然负载助催化剂是提高光电极效率研究最为广泛的策略之一，但对其功能的理解仍存在争议。我们以赤铁矿为模型体系，构建了含钴基分子立方烷助催化剂的新型混合分子光阳极。光电化学和速率定律分析揭示了{Co(II)O}型助催化剂有趣的功能转变。在调制外加偏压时，它们的作用从主要的空穴储存器转变为催化中心。光电化学过程的动力学分析表明，观察到的这种转变源于光生表面电荷载流子的动态平衡。最重要的是，我们证实了几种钴基分子催化剂和多相催化剂的助催化剂功能转变及相关动力学性质，表明所推导趋势具有广泛适用性。此外，补充分析表征表明，在较高外加偏压下会发生所施加分子物种的转变，这表明分子催化和多相催化之间存在动态相互作用。我们的见解有助于深入理解高效（分子）助催化光电极体系，从而设计出适用于广泛催化应用的定制混合器件。
