The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

• Published in: Nanomaterials (Basel, Switzerland) Vol. 12; no. 3; p. 433
• Main Authors: Zhang, Jiaqi, Li, Jin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.01.2022; MDPI
• Subjects: Ammonia; Catalytic activity; Composite materials; Efficiency; Electric potential; Electrodes; Electron paramagnetic resonance; Electron spin resonance; gas sensitivity; heterojunction; Heterojunctions; Lattice vacancies; Metal oxides; Methylene blue; Nanomaterials; Nanoparticles; Nanotechnology; Nickel oxides; Nitrates; Oxygen; oxygen vacancy; P-n junctions; Photocatalysis; Photoelectron spectroscopy; Photoelectrons; Photoluminescence; Photons; Potential fields; Recovery time; Response time; Room temperature; Scanning electron microscopy; Selectivity; Sensitivity analysis; Sensors; Spectroscopy; Synergistic effect; Vacancies; Water pollution; Work stations; X ray photoelectron spectroscopy; X-ray diffraction; Zinc oxide; Zinc oxides; ZnO/NiO; United States > US; China; Japan; Germany; photocatalysis; ZnO/NiO; gas sensitivity; heterojunction; oxygen vacancy
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12030433

In this paper, ZnO/NiO composites rich in oxygen vacancies are prepared by the solvothermal method and reduction method. In the test, through the use of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and electron paramagnetic resonance (EPR), we effectively prove the existence of phase, morphology and oxygen vacancies in the material. Through the photocatalysis test and gas sensitivity test, it is found that 10% Ni doped OZN-10 has the best photocatalytic activity and gas sensitivity characteristics. The degradation rate of methylene blue (MB) was 98%. The gas sensitivity test shows that OZN-10 has good selectivity, good response performance (3000 ppm, 27,887%) and excellent response recovery time (response time: 50 s, recovery time: 5-7 s) for saturated NH gas at standard atmospheric pressure (101.325 KPa) and room temperature (25 °C). The synergistic effect of oxygen vacancy as the center of a trap and p-n heterojunction forming an electric potential field at the interface is explained, and the mechanism of improving photocatalysis and gas sensitivity is analyzed. This work will provide an innovative vision for dual-performance oxygen vacancy modification of heterojunctions through photocatalysis.