Design of photocatalysts with high-efficiency for sunlight utilization is one of the prerequisites for CO 2 photoreduction . Besides, modulating a stable electron-donating environment to meet the energy barrier for CO 2 reduction to CO is crucial. In this work, the ZnSe/Ag 2 Se/AgBr (ZAA) heterojunction was fabricated by growing the ZnSe on the AgBr surface accompanied by in-situ generation of Ag 2 Se between the two components by hydrothermal process. Results showed that the ZAA exhibited excellent light response ability over the full wavelength range. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) demonstrated that the charge transfer of the ZAA conformed to dual Z-scheme mechanism, with the Ag 2 Se acting as an electron transfer bridge, which in turn acted as an electron reservoir to accelerate electron transfer, facilitating carriers’ separation. The highest CO yield of 54.14 µmol/g/h was obtained from the optimal ZAA-2, which was 11.76 and 10.44 times of pure ZnSe and Ag 2 Se, respectively. This work demonstrated the feasibility of a dual Z-scheme heterostructure with full spectrum response for offering stable electron-donating environment and improving electron transfer for enhanced photocatalytic activity.
A novel photoelectrochemical (PEC) aptasensor coupled with a Z‑scheme was developed to realize quantitative determination of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) at a concentration of sub-picogram per liter. The PEC aptasensor was fabricated by immobilizing ZnSe/Ag 2 Se on indium-tin oxide (ITO) that could covalently bind sulfurized aptamer. Meanwhile, complementary DNA-functionalized CdTe units were used as the sensitizers, and these were immobilized on the aptamer to form Z‑scheme dual-photosystem (PS). The Z‑scheme PS based on both ZnSe/Ag 2 Se and CdTe would be provided with better photocatalytic activity than conventional heterojunctions , and improving the photo-to-current conversion efficiency without biased voltage. Following the process of hatching, PCB77 was captured via the aptamer on the PEC aptasensor, producing aptamer–PCB77 complexes with weak conductive performance. Using the photocurrent change as a response signal for the quantitative detection of PCB77, the detection limits of the proposed method were 0.05 pg L –1 and 0.22 ng L –1 for the linear ranges of 0.01–500 pg L –1 and 0.5–10 5 ng L –1 , respectively. Compared with other technologies, the PEC aptasensor is more flexible, sensitive, specific and rapid in the absence of biased voltage under visble light. The results presented herein can potentially help build a model for the detection of various polychlorinated biphenyls (PCBs) with stable chemical properties and insulation performances that can be used to study persistent organic pollutants (POPs) in marine organisms and in the analysis of environmental conditions.
危险品化学品经营许可证（带存储）