Novel n–p Photocatalysts Heterojunction via ZnO Nanoparticles Decorated ZnCo2O4 as an Improved Visible-Light-Driven Decomposition of Methylene Blue and Antimicrobial Activity

A visible light-based photocatalyst system “green” solution for treating organic pollutants and microbes has been studied as a possible solution because it is cheap, can be recycled, and works very well. This study synthesized the n – p x .0ZnO/ZnCo 2 O 4 ( x = weight ratio of ZnO/ZnCo 2 O 4 ) heterostructure by co-precipitation method combined ultrasonic and tested its degradation of methylene blue (MB) and antibacterial activity. The structure, morphology, and chemical bonds of x .0ZnO/ZnCo 2 O 4 were tested via X-ray diffraction (XRD), Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and energy-dispersive X-ray analysis. X-ray diffraction (XRD) of the heterogeneous material x .0ZnO/ZnCo 2 O 4 revealed only two structures: the spinel ZnCo 2 O 4 and the ZnO hexagonal wurtzite. The absorption edge of x .0ZnO/ZC had a redshift and increased remarkable intensity absorption. The effective degradation efficiency of the ZnO/ZnCo 2 O 4 nanocomposite was 7.0, with a degradation efficiency of 96.5% MB. Heterojunction reduces electron–hole pair recombination, forming charge densities at the n -ZnO surface or holes at p -ZnCo 2 O 4 , promoting photocatalytic activity. 7.0ZnO/ZnCo 2 O 4 heterojunction has a photocurrent value of 4.70 µA/cm 2 , which is higher than 4.5 and 7.3-fold compared to ZnO and ZnCo 2 O 4 pure and has the smallest semicircle of AC impedance spectroscopy. This study also found that the n – p heterojunction of 7.0ZnO/ZnCo 2 O 4 could completely inactivate Escherichia coli and Staphylococcus aureus . After the photocatalytic reaction, the ZnO/ZnCo 2 O 4 photocatalysts were reused four times, which showed that they could be used again and were stable even after being exposed to light.