Insights into Photoinduced Carrier Dynamics and Overall Water Splitting of Z‑Scheme van der Waals Heterostructures with Intrinsic Electric Polarization

• Published in: The journal of physical chemistry letters Vol. 14; no. 3; pp. 798 - 808
• Main Authors: Wang, Juan, Zhang, Xuejin, Song, Xiaohan, Fan, Yingcai, Zhang, Zhihua, Zhao, Mingwen
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26.01.2023
• Subjects: Physical Insights into Energy Science
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.2c03742

Using first-principles calculations in combination with nonadiabatic molecular dynamics (NAMD), we propose novel heterostructures of carbon nitride (C7N6) and the Janus GaSnPS monolayer as promising direct Z-scheme photocatalysts for solar-driven overall water splitting. The out-of-plane electric field due to the electric polarization which is dependent on the stacking pattern alters the band alignment and catalytic activity of the heterostructures. The relatively strong interfacial nonadiabatic coupling and long quantum coherence time accelerate the interlayer carrier recombination, enabling a direct Z-scheme photocatalytic mechanism. More importantly, the redox ability of the remanent photogenerated carriers in the Z scheme is strong enough to trigger both the hydrogen evolution reaction (HER) and oxygen reduction reaction (OER) simultaneously without the help of sacrificial agents. Our work reveals a fundamental understanding of ultrafast charge carrier dynamics at vdW heterointerfaces as well as new design prospects for highly efficient direct Z-scheme photocatalysts.