Computational Design of a Strain-Induced 2D/2D g-C3N4/ZnO S-Scheme Heterostructured Photocatalyst for Water Splitting

Chadawan Khamdang, Sirisak Singsen, Apinya Ngoipala, Ittipon Fongkaew, Anchalee Junkaew, Suwit Suthirakun

Research output: Contribution to journalArticlepeer-review

Abstract

Electron-hole recombination is one of the major issues inhibiting practical use of photocatalysts for water splitting to generate clean hydrogen energy. Engineering a heterostructure with an S-scheme heterojunction has been reported to promote e-h separation and maximize potential of photogenerated charge carriers, which, in turn, dramatically improve photocatalytic activity. Herein, based on density functional calculations, we proposed a design of a 2D/2D g-C3N4/ZnO heterostructure to achieve an S-scheme heterojunction with high catalytic activity toward the overall water splitting reaction. We find that the heterostructure constructed from high tensile strain of the ZnO monolayer and the equilibrium g-C3N4monolayer exhibits an S-scheme heterojunction. The built-in electric field generated at the interface effectively separates electrons to locate at the g-C3N4side and holes at the ZnO side leading to lower e-h recombination. The heterostructure improves sunlight utilization where its absorption edge is red-shifted into the visible-light region with a higher absorption coefficient when compared to that of individual monolayers. In addition, the mechanistic study reveals that potential of holes at the valence band of the ZnO side can overcome the potential limiting step of the oxygen evolution reaction, while the hydrogen evolution reaction prefers to occur at the g-C3N4side, which is also where the electrons are accumulated. Our study demonstrates how we can rationally design high-performance 2D/2D heterostructure photocatalysts for overall water splitting based on first-principles modeling.

Original languageEnglish
Pages (from-to)13997-14007
Number of pages11
JournalACS Applied Energy Materials
Volume5
Issue number11
DOIs
Publication statusPublished - 28 Nov 2022
Externally publishedYes

Keywords

  • density functional theory
  • g-CN
  • heterostructure
  • photocatalytic water splitting
  • S-scheme heterojunction
  • ZnO

Fingerprint

Dive into the research topics of 'Computational Design of a Strain-Induced 2D/2D g-C3N4/ZnO S-Scheme Heterostructured Photocatalyst for Water Splitting'. Together they form a unique fingerprint.

Cite this