Effects of chlorinated Pd precursors and preparation methods on properties and activity of Pd/TiO2 catalysts |
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Authors: | Ye Eun Kim Mi Yeon Byun Kwan-Young Lee Man Sig Lee |
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Institution: | Ulsan Division, Korea Institute of Industrial Technology (KITECH), Ulsan 44413 Republic of Korea.; Department of Chemical and Biological Engineering, Korea University, Seoul 02841 Republic of Korea.; Department of Polymer Science and Chemical Engineering, Pusan National University, Busan 46241 Republic of Korea ; Department of Green Process and System Engineering, University of Science and Technology (UST), Ulsan 44413 Republic of Korea |
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Abstract: | We investigated the effects of Pd precursors and preparation methods on the physicochemical properties and performance of Pd/TiO2 catalysts in the photocatalytic degradation of methyl violet. To confirm the influence of the precursors, Pd/TiO2 catalysts were prepared via chemical reduction (CR) using four different Pd precursors. Additionally, to determine the effects of preparation methods, Pd/TiO2 catalysts were fabricated using K2PdCl4 precursor via three different methods: CR, deposition–precipitation (DP), and impregnation. The CO chemisorption results showed that the catalyst prepared via DP using the K2PdCl4 precursor, i.e., Pd/TiO2_K_DP, displayed the highest Pd dispersion of 12.42% owing to the stable formation of Pd(OH)2, which strongly interacted with the –OH groups on the TiO2 support. Although the catalyst prepared via CR using the Pd(NH3)4Cl2·H2O (PA) precursor, i.e., Pd/TiO2_PA_CR, had the lowest Pd dispersion of 0.7%, it exhibited the highest absorption of 26% after 30 min in the dark. It was found that high Pd2+/Pd0 ratio in dark conditions adversely affected the absorption of MV owing to electrostatic repulsion between the cationic dyes and metal nanoparticles. However, the Pd dispersion and the specific surface area played a key role in the photocatalytic activity under UV irradiation. Pd/TiO2_K_CR with higher Pd dispersion showed the highest photocatalytic activity and reaction rate of 0.0212 min−1.We investigated the effects of Pd precursors and preparation methods on the physicochemical properties and performance of Pd/TiO2 catalysts in the photocatalytic degradation of methyl violet. |
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