Enhanced H<sub>2</sub>O<sub>2</sub> Upcycling into Hydroxyl Radicals with GO/Ni:FeOOH-Coated Silicon Nanowire Photocatalysts for Wastewater Treatment.

Ning, Rui; Kim, Sungsoon; Sun, Eddie; Jiang, Yue; Baek, Jihyun; Li, Yuzhe; Robinson, Ashley; Vallez, Lauren et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

There remains continued interest in improving the advanced water oxidation process [e.g., ultraviolet (UV)/hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)] for more efficient and environmentally friendly wastewater treatment. Here, we report the design, fabrication, and performance of graphene oxide (GO, on top)/nickel-doped iron oxyhydroxide (Ni:FeOOH, shell)/silicon nanowires (SiNWs, core) as a new multifunctional photocatalyst for the degradation of common pollutants like polystyrene and methylene blue through enhancing the hydroxyl radical (•OH) production rate of the UV/H<sub>2</sub>O<sub>2</sub> system. The photocatalyst combines the advantages of a large surface area and light absorption characteristics of SiNWs with heterogeneous photo-Fenton active Ni:FeOOH and photocatalytically active/charge separator GO. In addition, the built-in electric field of GO/Ni:FeOOH/SiNWs facilitates the charge separation of electrons to GO and holes to Ni:FeOOH, thus boosting the photocatalytic performance. Our photocatalyst increases the •OH yield by 5.7 times compared with that of a blank H<sub>2</sub>O<sub>2</sub> solution sample and also extends the light absorption spectrum to include visible light irradiation.