1. Enhancing Aqueous Chlorate Reduction Using Vanadium Redox Cycles and pH Control.
- Author
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Gao, Jinyu, Chen, Gongde, Fu, Qi, Ren, Changxu, Tan, Cheng, Wang, Yin, Liu, Haizhou, and Liu, Jinyong
- Subjects
X-ray photoelectron spectroscopy (XPS) ,catalyst ,chlorate ,electrochemical study ,palladium ,recycle ,redox ,vanadium - Abstract
Chlorate (ClO3-) is a toxic oxyanion pollutant from industrial wastes, agricultural applications, drinking water disinfection, and wastewater treatment. Catalytic reduction of ClO3- using palladium (Pd) nanoparticle catalysts exhibited sluggish kinetics. This work demonstrates an 18-fold activity enhancement by integrating earth-abundant vanadium (V) into the common Pd/C catalyst. X-ray photoelectron spectroscopy and electrochemical studies indicated that VV and VIV precursors are reduced to VIII in the aqueous phase (rather than immobilized on the carbon support) by Pd-activated H2. The VIII/IV redox cycle is the predominant mechanism for the ClO3- reduction. Further reduction of chlorine intermediates to Cl- could proceed via VIII/IV and VIV/V redox cycles or direct reduction by Pd/C. To capture the potentially toxic V metal from the treated solution, we adjusted the pH from 3 to 8 after the reaction, which completely immobilized VIII onto Pd/C for catalyst recycling. The enhanced performance of reductive catalysis using a Group 5 metal adds to the diversity of transition metals (e.g., Cr, Mo, Re, Fe, and Ru in Groups 6-8) for water pollutant treatment via various unique mechanisms.
- Published
- 2023