Fig. 4: Photocatalytic H2 evolution.

a Time course of photocatalytic hydrogen evolution under visible light irradiation (>420 nm) for BTH-1, 2, 3. b AQY of BTH-1, 2, 3 under different monochromatic light irradiation. c Periodic on/off photocurrent output of BTH-1, 2, 3 casted on FTO glass. d Electrochemical impedance spectroscopy Nyquist plots of BTH-1, 2, 3.