Synergizing n → π* electronic transition and plasmonic hot electron injection enhances carrier generation of S-doped carbon nitride decorated with Au nanoparticles for Cr(VI) degradation

Abstract

Promoting carrier separation has received much attention owing to attractive enhancement effects in improving the utilization efficiency of photo-generated carrier. However, the photocatalytic performance has remained limiting mainly due to lack of magnifying carrier generation fundamentally. Herein, carrier generation enhanced CNS0.6/Au-1 is established by loading ultrafine Au nanoparticles on S-doped carbon nitride (CNSx) for efficient hexavalent chromium degradation. CNSx can activate the n → π* electronic transition of carbon nitride besides keeping the original π → π* electronic transition. Plasmon-induced hot electron of Au nanoparticles merge with e− excited from π → π* and n → π* transition in CNSx increasing the amount of catalytically effective electrons, and the efficient carrier separation is also achieved. Near-infrared absorption CNS0.6/Au-1 exhibits a remarkable photo-reactivity for the degradation of Cr(Ⅵ), which can degrade 10 ppm Cr(Ⅵ) completely within 40 min. This work proposes a general strategy of increasing different types of electron transitions to promote carrier generation.