Plasmon-enhanced photocatalytic cumulative effect on 2D semiconductor heterojunctions towards highly-efficient visible-light-driven solar-to-fuels conversion.

The photocatalytic activity of a semiconductor is heavily influenced by its photocatalytic cumulative effect on the four consecutive photo-physiochemical processes, including light harvesting, charge separation, charge migration, and charge utilization. Herein, we proposed and synthesized the well-designed plasmonic Au@Pt/CdS/C 3 N 4 heterostructure to enhance the photocatalytic cumulative effect by simultaneously sensitizing the total four processes. [Display omitted] • Pt/CdS-selective-coated Au nanocubes are assembled onto C 3 N 4 nanosheets. • Plasmon-enhanced photocatalytic cumulative effect on the Au@Pt/CdS/C 3 N 4 heterostructure. • Plasmon-induced HET, RET, and LEFE processes are achieved simultaneously. • Photocatalytic activities of H 2 generation and CO 2 reduction are remarkably enhanced. The photocatalytic activity of a semiconductor is heavily influenced by its photocatalytic cumulative effect on the four consecutive photo-physiochemical processes, including (I) light harvesting, (II) charge separation, (III) charge migration, and (IV) charge utilization. However, it is still a tremendous challenge to enhance the photocatalytic cumulative effect by simultaneously sensitizing the total above I-IV processes of the semiconductor. Herein, we synthesized the well-designed plasmonic Au@Pt/CdS/C 3 N 4 heterostructure through assembling Pt/CdS-selective-coated Au nanocubes onto the two dimensional (2D) ultrathin C 3 N 4 nanosheets (NSs). We have also demonstrated that selectively coating CdS nanoparticle-clusters (NPCs) and Pt nanoparticles (NPs) onto the surfaces and edges of Au NCs could boost the II and III processes of the formed Au@Pt/CdS NCs based on the resonance energy transfer (RET) and "hot electron" transfer (HET) behaviors, respectively, due to the localized surface plasmon resonance (LSPR) of Au NCs. The assembly of the Au@Pt/CdS NCs onto the C 3 N 4 NSs formed lots of 2D Au/CdS/C 3 N 4 interface, where the Au-LSPR not only boosted the I process at the "type II" heterojunction regions of CdS/C 3 N 4 , but also improved the II process of C 3 N 4 NSs via the local electromagnetic field enhancement (LEFE). Furthermore, the quasi-2D porous structure of CdS NPCs increased the surface active-sites at the 2D CdS/C 3 N 4 interface, therefore enhancing the IV process. As such, when normalizing the effective active area as the Au@Pt/CdS/C 3 N 4 hetero-interface region, the plasmonic heterostructure exhibited the ∼ 17.2-fold and ∼ 14.3-fold enhancements on the photocatalytic H 2 evolution and CO 2 reduction as compared to the CdS/C 3 N 4 heterojunction, respectively. [ABSTRACT FROM AUTHOR]