Z-scheme N-doped K4Nb6O17/g-C3N4 heterojunction with superior visible-light-driven photocatalytic activity for organic pollutant removal and hydrogen production

A simple calcination method was employed to prepare a Z-scheme N-doped K4Nb6O17/g-C3N4 (KCN) heterojunction photocatalyst, in which the electronic structure of K4Nb6O17 was regulated by N-doping, and g-C3N4 was formed both on the surface and within the interlayer spaces of K4Nb6O17. The KCN composite showed profoundly improved photocatalytic activity for both H-2 generation and RhB degradation compared to its counterparts. This improved performance was attributed to the synergistic effects of N-doping, which broadened its light harvesting ability, and heterojunction formation, which increased the charge separation rate. The relatively low BET specific surface area of the KCN composite had little effect on its photocatalytic activity. Based on ESR spectroscopy studies, center dot O-2-, center dot OH, and h(+) are the main active species in the photocatalytic degradation of RhB. Thus, it is reasonable to propose a Z-scheme photocatalytic mechanism over the KCN composite, which exhibits the dual advantages of efficient charge separation and high redox ability. Our work provides a simple approach for constructing large-scale Z-scheme heterojunction photocatalysts with high photocatalytic performance. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.