Photoelectrochemical (PEC) aptasensor is a promising analysis platform with high selectivity and sensitivity. Exploration of photoelectric active material with excellent photoelectric conversion efficiency is the key condition to design a PEC aptasensor with excellent sensitivity. Herein, a PEC aptasensor was designed and constructed by g-C₃N₄/Bi₂₄O₃₁Cl₁₀ heterojunction as photoelectric active material for realizing sensitive detecting enrofloxacin (ENR) antibiotic. The formation of heterojunction can facilitate separation and transfer of photogenerated carriers and reduce the recombination rate, leading to the enhancement of photocurrent response compared to that of individual semiconductor. The ENR aptamer was introduced as the specific recognition element to realize excellent selectivity of the PEC aptasensor. Because ENR-aptamer complex can block the transfer of charge, the ENR-PEC aptasensor presented the decreased photocurrent response with the increasing of ENR concentration without external voltage. The developed ENR-PEC aptasensor presented excellent sensitivity and selectivity for detecting ENR with a detection range from 0.5 to 100 fM and a low detection limit of 0.167 fM (S/N = 3). The ENR-PEC aptasensor with good reproducibility may be potential for the determination of the actual samples.

光电化学（PEC）适体传感器是一种具有高选择性和灵敏度的有前途的分析平台。探索具有优异光电转换效率的光电活性材料是设计具有优异灵敏度的PEC适体传感器的关键条件。_{本文采用gC 3} N ₄ /Bi ₂₄ O ₃₁ Cl ₁₀设计构建了PEC适体传感器。异质结作为光电活性材料实现灵敏检测恩诺沙星（ENR）抗生素。异质结的形成可以促进光生载流子的分离和转移，降低复合率，与单个半导体相比，光电流响应增强。引入ENR适体作为特异性识别元件以实现PEC适体传感器的优异选择性。由于ENR-适体复合物可以阻断电荷的转移，ENR-PEC适体传感器在没有外部电压的情况下随着ENR浓度的增加呈现出降低的光电流响应。开发的 ENR-PEC 适体传感器对检测 ENR 具有出色的灵敏度和选择性，检测范围为 0.5 至 100 fM，低检测限为 0.167 fM (S/N = 3)。