Photodegradation of orange II dye using p-n junction NiO/TiO2 composite, and assessment of its biological activities

Abstract

The chemical reduction method was used to synthesize nickel oxide particles (NiO) and NiO supported on titanium dioxide (NiO/TiO2 nanocomposite). The composites were characterized through scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The morphological investigation showed that pseudocubic NiO are present in dispersed as well as agglomerated forms. Whereas NiO particles (<200 nm) are evenly deposited over the surface of TiO2 in NiO/TiO2 composite. The formation of NiO and NiO/TiO2 was also verified by XRD analysis. The synthesized NiO and NiO/TiO2 were used as photocatalysts for the degradation of Orange II (OII) dye. According to the degradation investigation, both NiO and NiO/TiO2 composite degraded OII dye more efficiently when exposed to UV light. The results indicated that NiO degraded 93% and NiO/TiO2 composites degraded approximately 96% of OII dye within 30 min. Both photocatalysts are highly sustainable and have significant OII dye degradation recyclability. Moreover, NiO and NiO/TiO2 exhibited promising bioactivities (antioxidant activity of 80%) against the pathogenic bacteria Citrobacter and Providencia, which is comparable with the standard ascorbic acid (88%).

Keywords

• TiO2
• Photodegradation
• Orange II
• Bioactivity
• Antioxidant activity