Accumulation of localized charge on the surface of polymeric carbon nitride boosts the photocatalytic activity

The random mobility of charge carriers is a main factor causing the low photocatalytic efficiency of g-C3N4. Thus, the controllable migration of charge carriers is a rational strategy to suppress the charge recombination and facilitate charge separation. Herein, an ethylenediamine modified g-C3N4 displays improved photocatalytic activity. The excellent charge separation efficiency is confirmed to be a key factor for the enhancement. The TEM observation after photo-depositing Pt nanoparticles and DFT calculations verify the accumulation of electrons on some areas of g-C3N4 surface. The increased -NH2 groups significantly tune the electronic structure of g-C3N4 after the modification. The generation of midgap states also affects the charge separation. Our reports provide a simple method to manage the migration of charge carriers and enable electrons directional transfer, which suppresses the recombination and improves the photocatalytic activity. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

The random mobility of charge carriers in g-C3N4 can lead to low photocatalytic efficiency. Controllable migration of charge carriers is proposed as a strategy to suppress charge recombination and facilitate charge separation. In this study, ethylenediamine modified g-C3N4 is found to exhibit improved photocatalytic activity, with enhanced charge separation being identified as a key contributing factor. TEM observation and DFT calculations reveal the accumulation of electrons on certain areas of the modified g-C3N4 surface. The introduction of -NH2 groups through modification significantly alters the electronic structure of g-C3N4, leading to the generation of midgap states that impact charge separation. This research offers a simple method to manage charge carrier migration and enable electron directional transfer, thereby suppressing recombination and enhancing photocatalytic activity.