Intrinsic Mechanisms of Morphological Engineering and Carbon Doping for Improved Photocatalysis of 2D/2D Carbon Nitride Van Der Waals Heterojunction

Abstract

Van der Waals (VDW) heterojunctions in a 2D/2D contact provide thehighest area for the separation and transfer of charge carriers. In this work, atop-down strategy with a gas erosion process was employed to fabricate a2D/2D carbon nitride VDW heterojunction in carbon nitride (g-C3N4) withcarbon-rich carbon nitride. The created 2D semiconducting channel in theVDW structure exhibits enhanced electricfield exposure and radiationabsorption, which facilitates the separation of the charge carriers and theirmobility. Consequently, compared with bulk g-C3N4and its nanosheets, thephotocatalytic performance of the fabricated carbon nitride VDWheterojunction in the water splitting reaction to hydrogen is improved by 8.6and 3.3 times, respectively, while maintaining satisfactory photo-stability.Mechanistically, thefinite element method (FEM) was employed to evaluateand clarify the contributions of the formation of VDW heterojunction toenhanced photocatalysis, in agreement quantitatively with experimental ones.This study provides a new and effective strategy for the modification andmore insights to performance improvement on polymeric semiconductors inphotocatalysis and energy conversion.