Ultrathin 2D/2D Cd_0.9Zn_0.1S/Co_0.85Se Schottky heterojunction for high-performance aromatic alcohol splitting to...

Heterojunction engineering, particularly 2D/2D heterojunction involving ultrathin 2D materials, has garnered increasing attention due to the combined advantages of 2D atomic-scale nanostructure and the heterojunction effect, offering significant potential for enhancing photocatalytic performances. Here, we synthesize an ultrathin 2D/2D Schottky heterojunction composed of ∼1.50 nm Cd_0.9Zn_0.1S nanosheets and ∼ 0.66 nm Co_0.85Se nanosheets via a simple electrostatic self-assembly strategy. This unique sub-5 nm ultrathin 2D/2D heterostructure forms extensive heterojunction interfaces with intimate contact, generating abundant charge-transfer pathways and numerous active sites, while significantly shortening the charge carrier diffusion length. Additionally, the integration of 2D Co_0.85Se enhances the adsorption of aromatic alcohols onto the Cd_0.9Zn_0.1S surface due to the altered electronic states caused by the formation of Schottky heterojunction. As a result, the ultrathin 2D/2D Schottky heterojunction effectively boosts photocatalytic splitting of biomass-derived aromatic alcohols, producing H₂ and aldehydes simultaneously. The optimized Cd_0.9Zn_0.1S/Co_0.85Se composite achieves H₂ and benzaldehyde production rates of 3948.2 and 3878.5 μmol g^-1 h^-1, approximately 5.8 times higher than pure Cd_0.9Zn_0.1S. The work demonstrates the potential for the fabrication of ultrathin 2D/2D heterojunctions for high-performance conversion of biomass and its derivates to produce H₂ and value-added chemicals.