Efficient Catalytic Reduction of Organic Pollutants Using Nanostructured CuO/TiO<sub>2</sub> Catalysts: Synthesis, Characterization, and Reusability
The catalytic reduction of organic pollutants in water is a critical environmental challenge due to the persistent and hazardous nature of compounds like azo dyes and nitrophenols. In this study, we synthesized nanostructured CuO/TiO<sub>2</sub> catalysts via a combustion technique, foll...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
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| Series: | Inorganics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-6740/12/11/297 |
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| Summary: | The catalytic reduction of organic pollutants in water is a critical environmental challenge due to the persistent and hazardous nature of compounds like azo dyes and nitrophenols. In this study, we synthesized nanostructured CuO/TiO<sub>2</sub> catalysts via a combustion technique, followed by calcination at 700 °C to achieve a rutile-phase TiO<sub>2</sub> structure with varying copper loadings (5–40 wt.%). The catalysts were characterized using X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR–FTIR) spectroscopy, thermogravimetric analysis-differential thermal analysis (TGA–DTA), UV-visible diffuse reflectance spectroscopy (DRS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS). The XRD results confirmed the presence of the crystalline rutile phase in the CuO/TiO<sub>2</sub> catalysts, with additional peaks indicating successful copper oxide loading onto TiO<sub>2</sub>. The FTIR spectra confirmed the presence of all the functional groups in the prepared samples. SEM images revealed irregularly shaped copper oxide and agglomerated TiO<sub>2</sub> particles. The DRS results revealed improved optical properties and a decreased bandgap with increased Cu content, and 4-Nitrophenol (4-NP) and methyl orange (MO), which were chosen for their carcinogenic, mutagenic, and nonbiodegradable properties, were used as model organic pollutants. Catalytic activities were tested by reducing 4-NP and MO with sodium borohydride (NaBH<sub>4</sub>) in the presence of a CuO/TiO<sub>2</sub> catalyst. Following the in situ reduction of CuO/TiO<sub>2</sub>, Cu (NPs)/TiO<sub>2</sub> was formed, achieving 98% reduction of 4-NP in 480 s and 98% reduction of MO in 420 s. The effects of the NaBH<sub>4</sub> concentration and catalyst mass were investigated. The catalysts exhibited high stability over 10 reuse cycles, maintaining over 96% efficiency for MO and 94% efficiency for 4-NP. These findings demonstrate the potential of nanostructured CuO/TiO<sub>2</sub> catalysts for environmental remediation through efficient catalytic reduction of organic pollutants. |
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| ISSN: | 2304-6740 |