Modulating crystal facets of photoanodes for photoelectrocatalytic scalable degradation of fluorinated pharmaceuticals in wastewater.

Fluorinated pharmaceuticals pollution has become an ever-increasing environmental concern due to its negative impacts. Photoelectrocatalytic (PEC) degradation system is a desirable approach to tackle the pollution problems. However, photogenerated charge separation and interfacial mass transfer are the main bottlenecks for improving the PEC degradation performance. Herein, we report a TiO ₂ photoanode with tuned (101)/(110) facets in situ grown on a Ti mesh substrate for PEC degradation of fluorinated pharmaceuticals. The exposure of (101) facets facilitates efficient photogenerated charge separation and the desorption of generated •OH radical. Besides, the three-dimensional (3D) architecture of photoanode promotes macroscopic mass transfer. This system performed complete defluorination of 5-fluorouracil and more than 75 % total organic carbon (TOC) removal efficiency. The apparent reaction rate constant of high (101) facet-exposed TiO ₂ grown on Ti mesh is up to 6.96 h ^-1 , 6‒fold faster than that of photoanode with low (101) facet-exposed TiO ₂ grown on Ti foil. It is demonstrated that a large-sized PEC system of 1200 cm ² can degrade 100 L of synthetic fluorinated pharmaceutical wastewater with more than 80 % elimination efficiency. This work showcases the facet and substrate modulated strategy of fabricating high-performed photoanode for PEC wastewater purification.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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