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The overuse of tetracycline, a broad-spectrum antibiotic, has posed a severe threat to both the ecological environment and public safety. This paper presents the one-step synthesis of Bi2O2S/Bi2O3 heterojunctions utilizing a simple and environmentally friendly chemical synthesis method. These heterojunctions were subsequently employed in the fabrication of photoelectrochemical sensors tailored for tetracycline detection. Under optimal conditions, with a bias voltage of 0 V, the sensor manifests exceptional self-powered capability, yielding a photocurrent density of approximately 270nA/cm2. The detection sensitivity for tetracycline spans a wide linear range from 0.1 pM to 200 nM, accompanied by a remarkably low detection limit of 0.5 pM (S/N = 3). Furthermore, the photoelectrochemical sensor demonstrates commendable stability, rapid response characteristics, high selectivity, and consistent detection reproducibility. These findings not only offer a novel opportunity for advancing photoelectrochemical sensors but also present a fresh perspective in the realm of photoelectrochemical sensor development.

Tetracycline hydrochloride (TC-HCl) as an antibiotic is widely used in our daily life, but it has posed potential threats to the ecological environment for flowing into the natural environment. To address this issue, The photoelectrochemical (PEC) sensor is first developed for the detection of TC-HCl by comparing and analyzing ternary Bi2(Te1-xSex)3 nanomaterials prepared through different ratios of hydrothermal methods. Specifically, the Bi2(Te1-xSex)3/Indium tin oxide (ITO) electrode can interact with TC-HCl rapidly and selectively which results in a significant reduction of the photocurrent signal. By regulating the ratio of x, it is found that Bi2Te2.85Se0.15/ITO have the best stability and the fastest response time in the detection of TC-HCl. The response/recovery speed of the sensor to TC-HCl is fast to 0.23 s, a low detection limit of 0.08 pmol/l (S/N = 3) and a linear detection fit of up to R2 = 0.992. Moreover, the sensor has good stability and specificity for TC-HCL detection, providing a new perspective for the development of PEC sensors.

The overuse of mixed pesticides poses a threat to both the ecosystem and human health, yet general pesticide detection methods are complex in terms of steps, such as the need for pretreatment and cleaning. Surface-enhanced Raman scattering (SERS) has been used for real-life trace detection of residues due to its rapid detection and ultra-high sensitivity. Here, we prepared a novel Ti3C2Tx (MXene)-noble metal hybrid flexible substrate with a layer of MXene on top of flower-like Ag nanoparticles (AgNFs), and finally grew Au nanoparticles (AuNPs) by galvanic replacement and self-reduction reactions. The limit of detection (LOD) can be as low as 2 × 10-12 M by detecting 4-mercaptobenzoic acid (4MBA). For efficient sampling, transparent and flexible platform made of polydimethylsiloxane (PDMS) were used for the extraction and detection of thiabendazole (TBZ), thiram, methyl parathion (MP) and their mixtures. Notably, the lowest concentrations detected by swabbing on the tomato surface (3.7 ng/mL, 2.8 ng/mL) were lower than the EU maximum permissible limits of pesticides on raw fruits and vegetables (4.0 mg/L, 6.33 mg/mL). This high performance Ti3C2Tx-noble metal hybrid flexible substrate offers a great advantage in the trace detection of molecules.