NiO load K2Fe4O7 enhanced photocatalytic hydrogen production and photo-generated carrier behavior

•The application of K2Fe4O7 for photocatalytic hydrogen production was proposed.•Successfully synthesized NiO/K2Fe4O7 composite materials.•Surface photovoltage was used to research the behavior of photogenerated carriers. [Display omitted] 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 K2Fe4O7 for photocatalytic hydrogen production was proposed, and its photocatalytic performance was studied. Moreover, NiO was loaded on the surface of the K2Fe4O7, and improved the photocatalytic performance of K2Fe4O7. 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 K2Fe4O7 transferred to NiO, which enhanced the separation and transport of photogenerated carriers.