(527f) Synthesis of n-Type Metal Doped Molybdenum Diselenide for the Efficient Visible-Light Photocatalytic Degradation of an Antibiotic and Photo-Electrochemical Study

In recent decades, the discharge of pharmaceuticals into aquatic environments has raised human concern. These pharmaceuticals in waters are derived from hospitals, domestic effluent, and pharmaceutical industries containing excreted or unused medications. Current research findings revealed that the COVID-19 pandemic gave rise to a 102.2% average surge in waste production in both private and government healthcare facilities. The literature contains numerous studies that have documented the levels of CIP in various sources, including as wastewater treatment plants, untreated drinking water, hospital wastewater, lakes, and discharges from pharmaceutical companies. The concentrations vary between 11 and 99 mg/L, 0.032 mg/L, 150 mg/L, 6.5 mg/L, and 31 to 50 mg/L, respectively [1]. The literature review indicates that semiconductor based AOPs can be used to effectively remove pharmaceuticals from wastewater. In order to facilitate the water splitting reaction, it is necessary to use catalysts that are highly active, stable, low cost, and abundant.

Molybdenum diselenide (MoSe₂), because of its advantageous flower like morphology and increased conduction band (CB) position, has the potential to be a very effective reducing photocatalyst for the degradation of emerging pollutants and water-splitting process [2]. The intrinsic bandgap value of semiconducting materials can be altered by metal doping, leading to the formation of intermediate energy levels. These energy levels help to separate the photogenerated carriers by increasing the concentration of charge carriers and making it easier for electrons to be trapped [3].

This work involves the production of novel molybdenum diselenide and the doping of zinc metal into it. Using techniques such as FESEM, EDX, XRD, Raman, FTIR, and XPS, extensive investigations will be conducted, which will support the catalyst's efficient production. Using UV-VIS DRS to assess the synthetic sample's optical characteristics, it is possible to identify a band gap that promotes effective visible light absorption. The semiconductor type, charge transfer kinetics, and charge separation and transfer inside the on and off zones will be investigated using the Mott-Schottky plot, Electrochemical Impedance Spectroscopy (EIS) study, and photocurrent investigation, respectively. An appropriate photochemical reactor is used to break down ciprofloxacin (CIP), and the reaction rate constant is measured. Under optimal conditions, the residual concentration of CIP decreased to a point where it is no longer detectable after 45 minutes. Water-splitting will be investigated using chronoamperometry linear sweep voltammetry (LSV), Tafel plot and electrochemically active surface area (ECSA).

References

[1] T. Hayri-Senel, E. Kahraman, S. Sezer, N. Erdol-Aydin, G. Nasun-Saygili, Photocatalytic degradation of ciprofloxacin from water with waste polystyrene and TiO2 composites, Heliyon 10 (2024) e25433. https://doi.org/10.1016/j.heliyon.2024.e25433.

[2] J. Yang, J. Sun, S. Chen, D. Lan, Z. Li, Z. Li, J. Wei, Z. Yu, H. Zhu, S. Wang, Y. Hou, S-scheme 1 T phase MoSe2/AgBr heterojunction toward antibiotic degradation: Photocatalytic mechanism, degradation pathways, and intermediates toxicity evaluation, Sep Purif Technol 290 (2022) 120881. https://doi.org/10.1016/j.seppur.2022.120881.

[3] X. Li, Y. Cheng, Q. Wu, J. Xu, Y. Wang, Synergistic effect of the rearranged sulfur vacancies and sulfur interstitials for 13-fold enhanced photocatalytic H2 production over defective Zn2In2S5 nanosheets, Appl Catal B 240 (2019) 270–276. https://doi.org/10.1016/j.apcatb.2018.09.008