Significant enhancement in photocatalytic activity of (GaN)1−x(ZnO)x nanowires via solubility and crystal facet tailoring

Bofan Ren,Xin Wang,Ming Zhao,Defa Wang,Jinhua Ye,Xueliang Zhang

doi:10.1063/1.5009307

Abstract

We report on the solubility and crystal facet tailoring of the wurtzite structured (GaN)1−x(ZnO)x solid solution nanowires via a chemical vapor deposition method. With increasing the growth temperature from 900 °C to 1000 °C, the nanowire morphology is changed from zigzag to straight, and the band gap is increased from 2.70 eV to 3.26 eV, due to decreased solubility of ZnO. Photoelectrochemical and photocatalytic performances of the zigzag nanowires are significantly improved because of the narrower band gap for absorbing more solar light and the special lateral surface atomic structure favorable for the separation of photoinduced electrons and holes.

Highlights

Photocatalysis using semiconductor and solar light is widely regarded an ideal green technology for solving the global environmental pollution and energy shortage issues.[1,2,3] In last several decades, a lot of semiconductor materials have been developed as photocatalysts.[4,5,6,7] For example, GaN and ZnO were used for photocatalytic water splitting and carbon dioxide reduction while the reactions were valid only under UV light because of the wide band gaps of GaN (∼3.4 eV) and ZnO (∼3.2 eV).[6,8,9,10]
Previous theoretical calculation and experimental results revealed that the conduction band (CB) bottom of (GaN)[1]x(ZnO)x solid solution was mainly composed of Ga 4s and 4p orbitals; whereas, the valence band (VB) top was constructed by N 2p and Zn 3d orbitals, and the p d repulsion raised the VB top.[18,19]
A recent research found that the surface atomic structure of (GaN)[1]x(ZnO)x solid solution nanowire was closely related to the concentration of ZnO,[38] since a doping-induced stress effect was produced by the bond-length mismatch between doping elements and major elements

Summary

Introduction

Photocatalysis using semiconductor and solar light is widely regarded an ideal green technology for solving the global environmental pollution and energy shortage issues.[1,2,3] In last several decades, a lot of semiconductor materials have been developed as photocatalysts.[4,5,6,7] For example, GaN and ZnO were used for photocatalytic water splitting and carbon dioxide reduction while the reactions were valid only under UV light because of the wide band gaps of GaN (∼3.4 eV) and ZnO (∼3.2 eV).[6,8,9,10]. Significant enhancement in photocatalytic activity of (GaN)1−x(ZnO)x nanowires via solubility and crystal facet tailoring

Results

Conclusion