Zhu Kaijian, Frehan Sean Kotaro, Mul Guido, Huijser Annemarie
PhotoCatalytic Synthesis Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, AE Enschede 7500, the Netherlands.
J Am Chem Soc. 2022 Jun 22;144(24):11010-11018. doi: 10.1021/jacs.2c04301. Epub 2022 Jun 8.
Photoelectrochemical (PEC) cells containing photocathodes based on functionalized NiO show a promising solar-to-hydrogen conversion efficiency. Here, we present mechanistic understanding of the photoinduced charge transfer processes occurring at the photocathode/electrolyte interface. We demonstrate via advanced photophysical characterization that surface hydroxyl groups formed at the NiO/water interface not only promote photoinduced hole transfer from the dye into NiO, but also enhance the rate of charge recombination. Both processes are significantly slower when the photocathode is exposed to dry acetonitrile, while in air an intermediate behavior is observed. These data suggest that highly efficient devices can be developed by balancing the quantity of surface hydroxyl groups of NiO, and presumably of other p-type metal oxide semiconductors.
包含基于功能化氧化镍（NiO）光阴极的光电化学（PEC）电池展现出了颇具前景的太阳能到氢能的转换效率。在此，我们阐述了在光阴极/电解质界面发生的光致电荷转移过程的机理认识。我们通过先进的光物理表征证明，在NiO/水界面形成的表面羟基不仅促进光致空穴从染料转移到NiO中，还提高了电荷复合速率。当光阴极暴露于干燥乙腈中时，这两个过程都明显变慢，而在空气中则观察到中间行为。这些数据表明，通过平衡NiO以及大概其他p型金属氧化物半导体的表面羟基数量，可以开发出高效器件。
