Construction of Z-scheme heterostructure with enhanced photocatalytic H₂ evolution for g-C₃N₄ nanosheets via loading porous silicon

In this work, Z-scheme heterostructure were constructed over the visible light response g-C₃N₄ photocatalysts by loading Porous silicon (PSi) to enhance the photocatalytic H₂ evolution performance. The synthesized Z-scheme g-C₃N₄/PSi composites with a PSi loading content of 2.50 wt% achieves the highest photocatalytic H₂ evolution rate at 870.4 µmol h⁻¹ g⁻¹, which is about 2 times as high as the pure g-C₃N₄ with H₂ evolution rate of 427.2 µmol h⁻¹ g⁻¹. Various techniques including XRD, SEM, TEM, FTIR, XPS, UPS, PL and electrochemical method were employed to demonstrate the successful construction of g-C₃N₄/PSi composites and to investigate the origin of the enhanced potocatalytic activity. The formed heterostructure between g-C₃N₄ nanosheets and PSi were verified to be the dominant reason for the enhancement of photocatalytic activity, resulting from the separation promotion of photogenerated charge carriers in a direct Z-scheme mechanism. This study presented a promising Z-scheme g-C₃N₄/PSi photocatalysts with promising H₂ evolution performance, which might drive the progress of solar energy conversion technologies.