The photocatalytic hydrogen evolution of g–C3N4/K0.5Na0.5NbO3 nanofibers heterojunction under visible light

• Nanofibres heterojunction were synthesized by electrospinning and heat-treat. • The rate of the optimum heterojunction is 1.7 times than mechanical mixing. • The negative shift of band edge is the reason for the enhancement of activity. In this paper, g–C 3 N 4 /K 0.5 Na 0.5 NbO 3 nanofibers heterojunction were synthesized via electrospinning and facile heat-treat method. According to XRD, Raman, SEM, TEM and XPS analysis, a heterojunction structure was formed in g–C 3 N 4 /K 0.5 Na 0.5 NbO 3 nanofibers. Electrochemical impedance spectroscopy and transient photocurrent analysis indicated that 20 wt % g–C 3 N 4 /K 0.5 Na 0.5 NbO 3 had the best interfacial charge transfer reaction and high separation efficiency of photogenerated carriers. The rate of photocatalytic hydrogen evolution is 96.3 μmol·g −1 ·h −1 , which is 1.7 times that of simple mechanical mixed powders. This is attributed to the fact that the valence band maximum and conduction band minimum of g–C 3 N 4 /K 0.5 Na 0.5 NbO 3 nanofibers heterojunction are more negative than the mechanical mixed powders, and the difference value between them reaches the maximum when the content of g–C 3 N 4 is 20 wt %.