Photocatalytic oxidation of nitrogen oxides (NOx) using Ag- and Pt-doped TiO2 nanoparticles under visible light irradiation
2020
Abdelsalam, Essam M. | Mohamed, Yasser M. A. | Abdelkhalik, Saber | El Nazer, Hossam A. | Attia, Yasser Attia
In this work, titanium dioxide nanoparticles (TiO₂ NPs) and modified TiO₂ NPs with silver (Ag) or platinum (Pt) dopant were developed through photodeposition method for the NOₓ conversion into nitric acid (HNO₃) under visible light irradiation. The formed photocatalysts TiO₂, Ag/TiO₂, and Pt/TiO₂ nanocomposites were characterized by utilizing TEM, SEM, energy-dispersive X-ray analysis (EDX), XRD, UV/visible diffuse reflectance spectroscopy (UV-Vis DRS), and FT-IR. It had been investigated that an enhancement within the conversion of NOₓ into HNO₃ was increased from 34.3 to 78.3% for Ag/TiO₂ and from 35.2 to 78.5% for Pt/TiO₂ under visible light irradiation conditions at room temperature for less than 2 h. The photodegradation rate order of NOₓ under visible light irradiation is Pt/TiO₂ ~ Ag/TiO₂ > TiO₂. A possible mechanism for the catalytic conversion of NOₓ gases has been proposed, which depends on the photogeneration of electrons and holes after the excitation of nanocatalysts under visible radiation that promoted superoxide and hydroxyl ions, which can depredate NOₓ gases. This approach of NOₓ photocatalytic conversion is characterized by its chemical stability, low cost, high efficiency, simple operation, and strong durability than traditional methods.
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