Carbon quantum dots based charge bridge between photoanode and electrocatalysts for efficiency water oxidation

Xiao Jiang, Zemin Zhang, Junfeng Mei, Dongyan Han, Mingzheng Xie, Fangcong Wang, Erqing Xie, Weihua Han

Index: 10.1016/j.electacta.2018.04.052

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Abstract

Due to its earth abundant and excellent stability, metal oxide semiconductor attracts great attention in photoelectrochemical water splitting. However, its performance is restricted due to the high recombination rate of electron-hole pairs even modified with electrocatalysts. In this work, carbon quantum dots are studied as the charge bridge to boost the charge transfer kinetics of cobalt phosphate (Co-Pi)/Fe2O3 photoanode at the photoanode/electrocatalyst interface. Our results show that carbon quantum dots significantly improve the charge transfer and charge separation efficiency of Co-Pi/Fe2O3 photoanode. The photocurrent is substantially enhanced to 4.9 mA/cm2 at 0.6 V (vs. Ag/AgCl) which is much higher than Co-Pi/Fe2O3 photoanode 3.7 mA/cm2 in the same situation. These results provide a strategy to improve photoanode performance by facilitating the electrical contact at the photoanode/electrocatalyst interface with carbon quantum dots.