A Spatially Separated Organic–Inorganic Hybrid Photoelectrochemical Cell for Unassisted Overall Water Splitting

5 years ago

A Spatially Separated Organic–Inorganic Hybrid Photoelectrochemical Cell for Unassisted Overall Water Splitting

Lingcheng Zheng, Luyan Li, Feng Lu, Rongkun Zheng, Weichao Wang, Jie He, Lijun Zheng, Deqiang Feng, Hui Liu, Weihua Wang, Jianping Xu, Xinghua Zhang, Dawei Shao, Hong Dong, Yahui Cheng

The Z-scheme overall solar water splitting is a mimic of natural photosynthesis to convert solar energy into chemical fuels. Despite much effort, the available Z-scheme artificial systems are still rare, and most of them rely on inorganic semiconductors. In this study, inspired by the characteristics of p-type and higher unoccupied molecular orbital level of organic semiconductors, a spatially separated organic–inorganic hybrid Z-schematic photoelectrochemical (PEC) cell for unassisted overall water splitting is developed by wiring inorganic ZnO nanorod arrays photoanode and organic poly(3-hexylthiophene):[6,6]-phenyl-C₆₁-butyric acid (P3HT:PCBM) photocathode in a tandem manner. In the short-circuit configuration, the photocurrent density reaches an initial value of ∼78 μA cm^–2 and an average value of ∼95 μA cm^–2 under continuous UV–vis light irradiation, giving rise to the solar-to-fuel conversion efficiency of ∼0.12%. The average gas evolution rates are 1.59 μmol h^–1 for H₂ and 0.75 μmol h^–1 for O₂ under zero bias condition without sacrificial agents, corresponding to the faradic efficiency of ∼90%. These results demonstrate a possibility of introducing organic semiconductor into a Z-schematic system to realize unassisted overall solar water splitting, which enriches the practical Z-schematic photocatalytic systems.

Publisher URL: http://dx.doi.org/10.1021/acscatal.7b01002

DOI: 10.1021/acscatal.7b01002