Perovskite ferroelectric K 1−x Na x NbO 3 (x = 0, 0.05, 0.1, 0.3, 0.5, 0.7, and 1) nanofibers were prepared by electrospinning. The effects of Na doping on the photocatalytic hydrogen production of K 1−x Na x NbO 3 were studied. The results revealed that the best hydrogen production rates were at x = 0.5, which were 230.12 and 0.66 μmol•h −1 under simulated sunlight and visible light irradiation, respectively. Conversely, the corresponding hydrogen production rates of pure KNbO 3 were 155.90 and 0 μmol•h −1 , respectively. Through an analysis of Mott−Schottky plots, ultraviolet−visible spectra, and X-ray diffraction Rietveld refinement, the negative shift of the conduction band edge and the distortion of the NbO 6 octahedron may be the main reasons for the enhanced photocatalytic activity under simulated sunlight irradiation; the visible light response may be related to the shrinkage distortion of the NbO 6 octahedron. Moreover, the rate at which K 0.5 Na 0.5 NbO 3 nanofibers polarized under visible light irradiation was four times that without polarization, suggesting that the photogenerated carriers can be separated further by the internal depolarization field.

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