Enhanced Photocatalytic Hydrogen Generation by Optimized Plasmonic Hot Electron Injection in Structure-Adjustable Au-ZnO Hybrids

Youlong Chen,Sijing Ding,Liang Ma

doi:10.3390/catal10040376

Youlong Chen, Sijing Ding + Show 1 more

Open Access

https://doi.org/10.3390/catal10040376

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Abstract

Plasmonic Au-ZnO hybrids with adjustable structures (including Au-decorated ZnO and core–shell Au@ZnO with dense and porous ZnO shells) and the optimized hot electron-driven photocatalytic activity were successfully prepared. It was found that the Au@ZnO core–shell hybrids with porous morphology had the highest plasmon-enhanced photocatalytic hydrogen generation activity under visible light irradiation. The wavelength-dependent photocatalytic tests verified that Au@ZnO with porous ZnO shells had the highest apparent quantum efficiency upon resonance excitation. The ultrafast transient absorption measurements revealed that Au@ZnO with porous ZnO shells had the fastest plasmon-induced hot electron injection, which was thought to be the reason for the improved photocatalytic activity. This work might provide a promising route to designing photocatalytic and photoelectric materials.

Highlights

Hot electron-driven photocatalysis by plasmonic metal–semiconductor hybrids shows great potential in the field of solar energy conversion [1–10]
Hot electrons, which are generated from the nonradiative relaxation of localized surface plasmons, are more energetic than those generated by direct photoexcitation [11–15]
The current strategies mainly focus on adjusting the plasmonic properties of metal nanocrystals and the positions of semiconductors, and few reports concentrate on manipulating the morphology of semiconductors for better reception of hot electrons

Summary

Introduction

Hot electron-driven photocatalysis by plasmonic metal–semiconductor hybrids shows great potential in the field of solar energy conversion [1–10]. The maximum utilization of hot electrons is significantly important to improve the photocatalytic performance of metal–semiconductor hybrids [16–22]. Several strategies have been proposed to optimize the hot electron injection in plasmonic composites, such as enhancing the near field of plasmonic metal nanocrystals [23–25], selectively placing a semiconductor on the position, where a strong near field is located [26,27]. The current strategies mainly focus on adjusting the plasmonic properties of metal nanocrystals and the positions of semiconductors, and few reports concentrate on manipulating the morphology of semiconductors for better reception of hot electrons. Structure-adjustable Au-ZnO hybrids were used for optimizing hot electron-driven photocatalysis. Three types of Au-ZnO hybrids, including Au-decorated ZnO (Au/ZnO) and core–shell

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Conclusion