Fabrication of a Novel High-Performance p-CuO/n-ZnTiO3 Multifunctional Heterojunction Semiconductor with Photocatalytic, Electrocatalytic, and Antimicrobial Capabilities to Remove Various Environmental Pollutants

Abstract

Nowadays, due to the increase in the diversity and extent of environmental pollutants compared to before, the need for high-performance multifunctional semiconductors is felt more than ever to reduce costs and remove several different environmental pollutants at the same time. In the present research, the positive-copper oxide (p-CuO)/negative-zinc titanate (n-ZnTiO₃) as a novel multifunctional heterojunction semiconductor with photocatalytic, electrocatalytic, and antimicrobial capabilities to remove several different environmental pollutants such as rhodamine B (RhB) and methylene blue (MB) organic dyes, 4-chlorophenol antibiotic, and Escherichia coli and Staphylococcus aureus bacteria was synthesized. The crystal phase, morphology and particle size, and particle distribution were analyzed by XRD, FT-IR, Raman, SEM, and EDX/Map analyses. In addition, photocatalytic activity and surface porosity of p-copper oxide/n-zinc titanate semiconductor was analyzed by UV–visible, DRS, and BET devices. The UV–visible analysis indicated a photodegradation yield of 66.67 and 57.14% for rhodamine B (RhB) and methylene blue (MB) dye, respectively, in the presence of light irradiation in optimum experiment conditions of pH:7, temperature: 65 °C, mixing speed: 200 rpm, retention time: 5 h, p-copper oxide/n-zinc titanate value; 1 g/l, dyes value; 10 mg/l and distance between the irradiation source and solution surface: 10 cm. Electrocatalytic activity of p-copper oxide/n-zinc titanate semiconductor for degradation of 4-chlorophenol pollutant with a concentration of 0.0001 M was evaluated by cyclic voltammetry (CV) device in optimal conditions of N-icosane binder percentage: 5%, p-copper oxide/n-zinc titanate modifier value: 20%, pH 7, and scan speed: 300 mv/s. Also, after drawing the cyclic voltametric calibration curve of the 4-chlorophenol pollutant, the target sensor showed a linear behavior with a correlation coefficient of 0.9912. The response range of the sensor was 1.3–1000 μM and the limit of detection (LOD) was 0.93 μM. For the reproducibility of the measurements, the percentage of relative standard deviation (%RSD) was determined, which was measured to be 27.9% at a concentration of 0.75 μM. The increase in the intensity of the 4-chlorophenol oxidation current and the displacement of its oxidation potential in the obtained results indicated the electrocatalytic properties of p-copper oxide/n-zinc titanate semiconductor. Finally, the antimicrobial property of p-CuO/n-ZnTiO₃ semiconductor was investigated at concentrations of 0.15–70 mg/ml on E. coli and S. aureus bacteria. Based on the obtained results, the effective concentration of the desired p-copper oxide/n-zinc titanate semiconductor in inhibiting E. coli and S. aureus bacteria was determined at about 1.09 and 2.18 mg/ml, respectively. Eventually, the p-CuO/n-ZnTiO₃ multifunctional heterojunction semiconductor showed structural stability and reusability even after 5 cycles of continuous use. Also, the p-CuO/n-ZnTiO₃ multifunctional heterojunction semiconductor showed suitable performance and higher efficiency than other similar semiconductors synthesized in recent years.