Z-scheme heterostructure of ZnO@NPC/Au/ZnIn2S4 for chemical replacement reaction-mediated signal-on photoelectrochemical assay of mercury ion

• Published in: Microchemical journal 2024-12, Vol.207, p.111904, Article 111904
• Main Authors: Meng, Leixia, Wang, Jinlong, Xu, Zhouqing, Zhou, Bingxin, Shi, Jianjun, Xiao, Ke
• Format: Article
• Language: English
• Subjects: Chemical replacement reaction; Mercury ion; Metal organic framework-derived ZnO@NPC polyhedron; Photoelectrochemical sensor; Three-dimensional chrysanthemum-like ZnIn2S4; Z-scheme heterojunction
• ISSN: 0026-265X
• DOI: 10.1016/j.microc.2024.111904

[Display omitted] •A sensitive and facile PEC sensor for the detection of Hg2+.•An advanced MOF-derived ZnO@NPC/Au/ZnIn2S4 Z-scheme heterostructure.•Z-scheme heterostructure as optoelectronic material and Hg2+-recognition probe.•Chemical replacement reaction-mediated signal-on sensing strategy.•Good application prospect in food safety and environment field. Herein, an advanced Zn-based metal organic framework (Zn-MOF) derived ZnO embedded in a nitrogen-doped porous carbon (ZnO@NPC) polyhedron/Au/ three-dimensional (3D) chrysanthemum-like ZnIn2S Z-scheme heterojunction was employed for the chemical replacement reaction-mediated signal-on photoelectrochemical (PEC) sensing detection of mercury ions (Hg2+). The p-type ZnO@NPC polyhedron was initially prepared by carbonising the zeolitic imidazolate framework (ZIF)-8 polyhedron, followed by modification with Au nanoparticles (NPs) via an in situ photocatalytic reduction method. Subsequently, the ZnO@NPC/Au polyhedron was combined with n-type 3D chrysanthemum-like ZnIn2S4 through physical adsorption, forming the ZnO@NPC polyhedron/Au/3D chrysanthemum-like ZnIn2S4 Z-scheme heterostructure. The newly constructed heterostructure exhibited strong visible light–harvesting capacity, and considerably improved photoelectric conversion efficiency. The 3D chrysanthemum-like ZnIn2S4 functioned not only as a photosensitiser but also as an Hg2+ recognition probe. Importantly, the PEC sensor exhibited a considerably increased photocurrent response to Hg2+. This is presumably because the introduction of Hg2+ triggered a selective Zn-to-Hg chemical replacement reaction, leading to the in-situ formation of a ZnO@NPC/Au/ZnIn2S4/HgS heterojunction, which further improved charge separation. Consequently, Hg2+ was sensitively detected with a wide linear range from 0.5 pM to 2 μM and a low detection limit of 0.07 pM. Furthermore, the proposed sensor was validated by detecting Hg2+ in food and aqueous environments, indicating its potential application in food safety and environmental monitoring.