Improving the efficiency of photocatalytic water splitting hydrogen production of iron-containing metal oxide photocatalysts is still a huge challenge. Herein, the new application of K 2 Fe 4 O 7 for photocatalytic hydrogen production was proposed, and its photocatalytic performance was studied. Moreover, NiO was loaded on the surface of the K 2 Fe 4 O 7 , and improved the photocatalytic performance of K 2 Fe 4 O 7 . To understand the reason for the performance improvement, electrochemical impedance spectra, Surface photovoltage (SPV) and Transient photovoltage (TPV) were used to investigate the photogenerated carrier transportation mechanism of the samples. The result shows that the excellent photocatalytic performance of the samples was mainly due to the photogenerated electrons of K 2 Fe 4 O 7 transferred to NiO, which enhanced the separation and transport of photogenerated carriers.
In this work, hexagon-shaped potassium ferrite (K2Fe4O7) crystals with different sizes were prepared using the hydrothermal method. The crystals showed a narrow band gap of 1.44 eV, revealed by UV-visible diffuse reflectance spectroscopy, and was thus used as a heterogeneous Fenton catalyst to degrade methylene blue (MB) and crystal violet (CV) in the presence of green oxidant H2O2under visible-light irradiation. Among the investigated crystals, the as-prepared one with an average size of 20 µm (KFO-20) exhibited better photocatalytic activity due to its high surface area. When it was used as a photo-Fenton catalyst, 100% MB and 92% CV were degraded within 35 min. Moreover, the catalyst maintained high photocatalytic activity and was stable after four continuous cycles. The trapping experiments showed that the active hydroxyl radical (·OH) was dominant in the photo-Fenton reaction. Therefore, this new photo-Fenton catalyst has great potential for the photocatalytic degradation of dye contaminants in water.Keywords:K2Fe4O7;visible light;Fenton catalyst;degradation;methylene blue and crystal violet
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