Diethylenetriamine synergistic boosting photocatalytic performance with porous g-C3N4/CdS-diethylenetriamine 2D/2D S-scheme heterojunction

Abstract

To keep excellent redox ability and facilitate the separation of charge carriers, step-scheme (S-scheme) photocatalytic systems have been used in the photocatalytic H2 production. Recently, all kinds of photocatalysts with excellent performance and stability have been formed. Especially, 2D/2D heterojunction materials have attracted tremendous attention for the faster interfacial charge separation and transfer between them and much active centers. In this work, we designed a series of heterostructure photocatalysts of 2D/2D porous graphitic C3N4 (Pg-C3N4)/CdS-diethylenetriamine (DETA) nanocomposites and explored the S-scheme mechanism via density functional theory (DFT) calculations and XPS analysis. Under visible light irradiation, the experimental results indicated that the designed nanocomposites of water splitting photocatalytic activity for hydrogen evolution was 9738 μmol h−1 g−1, which is 1.7 and 12.2 times higher than that of CdS-DETA and Pg-C3N4. The performance improvement is mainly due to the following reasons: 1) Pg-C3N4 with large specific surface area could provide more active sites; 2) 2D/2D heterojunction have the faster interfacial charge separation and transfer rate; 3) DETA could synergistically promote the improvement of performance. This work not only introduces a novel Pg-C3N4/CdS-DETA heterojunction but also provides an approach on designing 2D/2D heterojunction for application in photocatalysis.