Amorphous surface modification and scalability of WO₃ nanostructures for photoelectrocatalytic degradation of organic pollutants

This work explores the use of WO₃ nanostructures as an effective solution for the removal of emerging contaminants from water, specifically focusing on the degradation of diethyl phthalate (DEP), a widely recognized environmental pollutant. A key aspect of the study is the scaling of the electrochemically active area and surface modification of WO₃ nanostructures, progressing from 0.5 cm² to 2.5 cm², followed by a surface reduction treatment that induces amorphization and enhances their photoelectrocatalytic activity after applying a 5-minute reduction treatment. Scaling was further extended to 15 cm², with the 15 cm² nanostructures exhibiting the highest DEP degradation rate, achieving a degradation constant of 0.0988 h⁻¹. The study also investigates the effect of key operational parameters such as applied voltage (1 V and 1.5 V), contaminant concentration (10 ppm, 25 ppm and 100 ppm). Reusability was also tested, with optimal conditions identified as 10 ppm DEP, 1 V, and the ability to reuse the nanostructures up to three times. Finally, under these optimal conditions, the degradation of DEP was monitored, leading to the identification of ten intermediate products and the proposal of a degradation pathway, highlighting the potential of WO₃ for sustainable and efficient water treatment applications.