Tuning the ZnO/GaN heterojunction for atmospheric NO abatement

• Published in: Applied surface science Vol. 635; p. 157712
• Main Authors: Yuan, Xuemei, Wu, Menglin, Ni, Jiupai, Cheng, Yongyi, Ni, Chengsheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.10.2023
• Subjects: (Ga, Zn)(N, O); Heterojunction; NO oxidation; Photocatalysis; ZnO nano-particles; NO oxidation; ZnO nano-particles; Photocatalysis; (Ga, Zn)(N, O); Heterojunction
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2023.157712

[Display omitted] •Microstructure and defect concentration were optimized by annealing in air.•In-situ growth of ZnO and GaN(O) to form a heterojunction.•Discrete ZnO directed migration of hot charge carriers.•ZnO/(Ga, Zn)(N, O) exhibited efficient NO oxidation under visible light irradiation.•NO preferentially adsorbed at the ZnO/(Ga, Zn)(N, O) interface. Photocatalysis was a green and sustainable strategy for environmental remediation as it could accelerate the degradation/oxidation of pollutants using the widely available solar energy as the driving force. The efficacy of photocatalysis could be improved by the formation of a heterojunction and microstructure optimization of the semiconducting catalysts to manipulate the transfer of hot charge carriers. The re-oxidation of a visible light photocatalyst, (Ga, Zn)(N, O) (ZGN), was used for the in-situ production of ZnO/GaN(O) heterojunction with different surface properties for efficient NO oxidation. Re-oxidation at different temperatures imparted the new state of the surface oxide of the substrate (ZGN) anion redistribution by the mode strain between the oxide and the nitride, leading to the transformation of material properties. The ZGN-550 (ZnO/GaN(O)) showed a significantly higher oxidation efficiency (90.2%) than the pristine ZGN (62.3%) under visible light insolation, because the nanoscale discrete ZnO over the oxynitride matrix promoted the separation of charge carriers and the formation of reactive radicals (•OH and •O2–). The ZGN-550 heterojunction obtained a high apparent quantum efficiency of about 6.64% at photons around 400 nm. ZnO/GaN(O) heterojunction has great potential for sustainable and efficient degradation of air pollutants.