PtS2/g-C3N4 van der Waals heterostructure: A direct Z-scheme photocatalyst with high optical absorption, solar-to-hydrogen efficiency and catalytic activity

• Published in: International journal of hydrogen energy 2023-05, Vol.48 (39), p.14659-14669
• Main Authors: Zhang, Yan, Qiao, Hui, Yan, Zheng-Hua, Duan, Li, Ni, Lei, Fan, Ji-Bin
• Format: Article
• Language: English
• Subjects: Electronic property; First-principles; Photocatalytic water splitting; PtS2/g-C3N4 heterostructure; Solar-to-hydrogen efficiency; Structural stability
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2022.12.329

Using two-dimensional semiconductors to build heterojunction as photocatalyst for water splitting is an important green and clean energy technology and has wide development prospects. Here, the monolayered PtS2 and g-C3N4 are used to build the direct Z-scheme van der Waals (vdW) heterostructure, and the structure, electrical, Bader charge, optical properties and solar-to-hydrogen efficiency are calculated in detail through first-principle calculations. The direct Z-scheme PtS2/g-C3N4 vdW heterostructure has an inherent type-II band alignment that enables it to reduce the photogenerated carriers aggregation, and it also possesses a decent band edge position to fully induce the redox reactions of decomposed water. The charge density shows that PtS2 monolayer is negatively charged while g-C3N4 monolayer is positively charged, and the interface potential drop of PtS2/g-C3N4 vdW heterostructure forms a built-in electric field with the direction from g-C3N4 to PtS2. The PtS2/g-C3N4 vdW heterostructure has suitable optical property, outstanding solar-to-hydrogen efficiency, high catalytic activity and thus a promising application prospect for photocatalytic water splitting. Band edge alignments of the PtS2 and g-C3N4 monolayers as well as the PtS2/g-C3N4 vdW heterostructure. [Display omitted] •PtS2/g-C3N4 heterostructure is a direct Z-scheme heterostructure.•PtS2/g-C3N4 heterostructure has a large built-in electric field from g-C3N4 to PtS2 layer.•PtS2/g-C3N4 heterostructure has a maximum absorption of 5.82×105cm−1 near 400 nm.•PtS2/g-C3N4 heterostructure has a high solar-to-hydrogen efficiency of 31.64 %.•PtS2/g-C3N4 heterostructure is a promising water-splitting photocatalyst.