Enhanced H<sub>2</sub>O<sub>2</sub> Upcycling into Hydroxyl Radicals with GO/Ni:FeOOH-Coated Silicon Nanowire Photocatalysts for Wastewater Treatment
R. Y. NING, Sungsoon Kim, Eddie Sun, Yue Jiang, Jihyun Baek, Yuzhe Li, Ashley M. Robinson, Lauren Vallez, Xiaolin Zheng
Abstract
There remains continued interest in improving the advanced water oxidation process [e.g., ultraviolet (UV)/hydrogen peroxide (H 2 O 2 )] 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 2 O 2 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 2 O 2 solution sample and also extends the light absorption spectrum to include visible light irradiation.