Plasma synthesis of K-doped amorphous carbon nitride with passivated trap states for enhanced photocatalytic H2O2 production

Abstract

Amorphous carbon nitride (ACN) is a promising semiconductor photocatalyst for photocatalytic H2O2 production. However, its actual activity is hindered by a high recombination rate of photoexcited charge carriers. Herein we report a K-doped ACN (K-ACN) photocatalyst synthesized via Ar plasma treatment to the modified melamine and KCl powder mixture at a moderate temperature. The as-synthesized K-ACN exhibits significantly enhanced photocatalytic properties for H2O2 production with a yield of 6.21 mM h−1, which is 6 times higher than that of bulk CN. Moreover, the H2O2 yield can be further increased to 13.95 mM h−1 by adjusting the pH value. The significantly enhanced photocatalytic property is mainly attributed to the introduction of K+, which is conducive to tuning the electronic structure, extending π conjugated system, passivating trap states and enhancing photocatalytic activity. The result has provided a facile and effective strategy for the modification of ACN to significantly boost its photocatalytic activity.