Carbon Nanofiber-Bridged Carbon Nitride-Fe 2 O 3 Photocatalyst: Hydrogen Generation and Degradation of Aqueous Organics

Graphitic carbon nitride (g-C 3 N 4 )-supported ferric oxide (Fe 2 O 3 ) nanocomposite modified with carbon nanofibers (CNFs) has been synthesized for the first time for photocatalytic H 2 -generation and the degradation of aqueous organics. In its first dual role, Fe 2 O 3 served as the photocatalyst and the chemical vapor deposition (CVD) catalyst to grow CNFs over the g-C 3 N 4 substrate. Time of CVD was found to be critical for synthesizing Fe 2 O 3 -CNF/g-C 3 N 4 with a good photocatalytic efficiency. The synthesized materials were characterized for various physicochemical and photocatalytic properties. The creation of a Z-scheme heterostructure between g-C 3 N 4 and Fe 2 O 3 resulted in the greater H 2 -generation rate (2095 µmol/g h) than that (1119 µmol/g h) over the substrate. The photocatalytic degradation data showed ~ 95 and 91% removal of methylene blue and 4-nitrophenol in 180 and 300 min, respectively at 22 °C using the Fe 2 O 3 -CNF/g-C 3 N 4 dose of 0.5 mg/mL. The photocatalytic reactions followed the indirect Z-scheme charge transfer path, with the graphitic CNFs acting as the electron-transfer medium between Fe 2 O 3 and g-C 3 N 4 . The simple fabrication route and high photocatalytic efficiency of the ternary CNF-bridged Fe 2 O 3 -g-C 3 N 4 composite system indicate the utility of the material in integrated environmental and energy applications including microbial fuel cells and microelectrolysis cells. Graphical Abstract