Research On Photoelectrochemical Sensing Applications Based On Metal Oxide Materials

Photoelectrochemical（PEC）analysis is an analytical technique based on semiconductor materials that utilizes the photoelectric conversion properties of these materials to convert information about the analyte into an electrochemical signal.This technique offers several advantages,such as low background noise,fast response times,and easy miniaturization.However,current PEC analysis methods suffer from weak resistance to matrix interference,low intelligence,and dependence on external bias voltages,resulting in low detection sensitivity,difficulties in on-site detection,and high energy consumption.To address these issues,this paper designed metal oxide photoelectrochemical materials with high photoelectric activity,and constructed high-sensitivity,intelligent,and self-powered PEC immune sensing detection technologies targeting small molecular pollutants in medical testing,environmental monitoring,and food safety.These technologies have important theoretical significance and practical value.The main content of this paper includes the following three aspects:（1）Development and application of Bi₂O₃/Cu Bi₂O₄-based photocathode sensing detection technologyTo improve the resistance to matrix interference in PEC sensing,a Bi₂O₃/Cu Bi₂O₄photocathode sensing detection technology was developed.Experimental testing and theoretical calculations were used to demonstrate the transfer path of photo-generated carriers within the heterojunction.Using aflatoxin B1 as the target analyte,under optimized conditions,the detection limit was 297.4 fg/m L,with a linear range of 1.4×10^-3-280 ng/m L,and the repeatability and reproducibility RSD were 1.17%and 3.12%,respectively,with a recovery rate of 91.4%-117.0%.When applied to complex matrices such as urine,lake water,peanuts,and wheat,the PEC detection results were highly consistent with the national standard methods,indicating its broad application prospects.（2）Development and application of Cu₂O/Cu₃Sn S₄-based photoelectrochemical intelligent detection technologyTo achieve intelligent PEC sensing detection,Cu₂O/Cu₃Sn S₄ nano-flower photocathode material was designed,and a PEC intelligent real-time detection technology platform was established using a smartphone to read PEC sensing detection signals.Experimental testing and theoretical calculations were used to demonstrate the transfer path of photo-generated carriers within the heterojunction.Using plasticizers（butyl benzyl phthalate）in the environment and food as the detection targets,under optimized conditions,the detection limit was 7.94 pg/m L,with a linear range of 0.04-400 ng/m L,and the repeatability and reproducibility RSD were0.62%and 2.90%,respectively,with a recovery rate of 87.9%-103.4%.This provides a new method for intelligent PEC detection.（3）Development and application of self-powered photoelectrochemical sensing detection technologyTo construct a new self-powered PEC sensing method,Ti O₂-P-N-Pd photoanode and Cu₂O/Cu₃Sn S₄ photocathode materials were designed and prepared.Using tetrabromobisphenol A（TBBPA）as the target analyte,the monoclonal antibody was immobilized on the photocathode to enhance the detection anti-interference ability,and a competitive immunoassay method was established through separation of biorecognition and photoelectrochemical signal conversion.The Fermi level difference between the photoanode and photocathode drove the photogenerated electrons to transfer along the external circuit,forming a self-powered system to improve the photoelectric conversion efficiency and detection sensitivity.Under optimized conditions,the detection limit was 8.41 pg/m L,the linear range was 0.02-400 ng/m L,repeatability and reproducibility RSD were 3.3%and 7.8%,respectively,which meets the detection requirements for environmental pollutants.