An ingenious molecularly imprinted photo-induced sensor for ultrasensitive determination of sulfadiazine based on the urchin-shaped Bi2S3

A novel molecularly imprinted electrochemical sensor based on quasi-three-dimensional nanomaterials Nb2CTx/AgNWs for specific detection of sulfadiazine

A novel molecularly imprinted electrochemical sensor (MIECS) was constructed for the specific detection of sulfadiazine (SDZ) in food. Niobium carbide (Nb2CTx) as a typical two-dimensional lamellar nanomaterial has good electrical conductivity and unique structure, which was assembled with one-dimensional silver nanowires (AgNWs) to form quasi-three-dimensional composite nanomaterials (Nb2CTx/AgNWs). As spacer material, AgNWs prevented the aggregation of Nb2CTx and the collapse of Nb2CTx layers. At the same time, a fast electron transport channel was constructed through the synergistic effect between nanomaterials the two. The Nb2CTx/AgNWs realized the enhancement of electrical signals. Molecularly imprinted polymers (MIPs) endowed the sensor with selectivity, achieving the specific detection of sulfadiazine. Under the optimal experimental conditions, the method has a wide linear range (1 × 10-8-1 × 10-4 mol L-1) and a low limit of detection (1.30 × 10-9 mol L-1). The sensor was used to detect sulfadiazine in pork, chicken, and feed samples, and the recovery was 82.61-94.87%. The results were in good agreement with the HPLC results, which proved the accuracy and practicability of the method.

Efficient degradation of bisphenol A with MoS2/BiVO4 hetero-nanoflower as a heterogenous peroxymonosulfate activator under visible-light irradiation

Photocatalyst activated peroxymonosulfate (PMS) under visible-light irradiation to construct a photo-Fenton system has shown great application prospect for environmental remediation. In this study, MoS₂/BiVO₄ heterojunction nanoflowers were successfully synthesized by hydrothermal method and used to activate PMS under visible-light to achieve highly efficient degradation of bisphenol A (BPA). The constructed heterojunction showed excellent catalytic activity, which was attributed to the synergistic effect of effective separation of charge carriers and PMS activation. In the MoS₂/BiVO₄/PMS/vis system, 2-MoS₂/BiVO₄ (2-MB) exhibited the highest degradation rate constant for BPA (0.1747 min^-1), which was 91.9 times of pure MoS₂ and 38.0 times of pure BiVO₄, respectively. The electron paramagnetic resonance (EPR) and radical quenching experiments demonstrated that the oxidative degradation of BPA was mainly participated by SO₄^-, OH, ¹O₂ and h⁺ active species. Through the analysis of energy band structure and element valence state of photocatalyst and the identification of reaction intermediates, the degradation mechanism and degradation pathways were proposed. In addition, MoS₂/BiVO₄ heterojunction showed high catalytic ability for various organic pollutants (herbicides, pesticide intermediates, antibiotics and dyes), and common anions (Cl^-, SO₄^2- and NO₃^-) and humic acid (HA) had little effect on its degradation efficiency. This study has provided a new solution for the use of heterojunction photocatalysts for visible-light assisted PMS activation to achieve highly efficient degradation of organic pollutants.

Bi2 S3 -In2 S3 Heterostructures for Efficient Photoreduction of Highly Toxic Cr6+ Enabled by Facet-Coupling and Z-Scheme Structure

The construction of Z-scheme photocatalyst materials mimicking the natural photosynthesis system provides many advantages, including increased light harvesting, spatially separated reductive and oxidative active sites and strong redox ability. Here, a novel Bi₂ S₃ nanorod@In₂ S₃ nanoparticle heterojunction photocatalyst synthesized through one-pot hydrothermal method for Cr⁶⁺ reduction is reported. A systematic investigation of the microstructural and compositional characteristics of the heterojunction catalyst confirms an intimate facet coupling between (440) crystal facet of In₂ S₃ and (060) crystal facet of Bi₂ S₃ , which provides a robust heterojunction interface for charge transfer. When tested under visible-light irradiation, the Bi₂ S₃ -In₂ S₃ heterojunction photocatalyst with 15% Bi₂ S₃ loading content achieves the highest Cr⁶⁺ photoreduction efficiency of nearly 100% with excellent stability, which is among the best-reported performances for Cr⁶⁺ removal. Further examination using optical, photoelectrochemical, impedance spectroscopy, and electron spin resonance spectroscopy characterizations reveal greatly improved photogenerated charge separation and transfer efficiency, and confirm Z-scheme electronic structure of the photocatalyst. The Z-scheme Bi₂ S₃ -In₂ S₃ photocatalyst demonstrated here presents promise for the removal of highly toxic Cr⁶⁺ , and could also be of interest in photocatalytic energy conversion.

A novel label-free photoelectrochemical aptasensor for the sensitive detection of ampicillin based on carbon-coated Bi2S3 nanorods

The prepared Bi2S3@C nanorods with remarkable photoelectrochemical properties served as a PEC sensor platform for the ultrasensitive analysis of ampicillin.

Visible-light-driven photoelectrocatalytic activation of chloride by nanoporous MoS2@BiVO4 photoanode for enhanced degradation of bisphenol A

The massive emission of bisphenol A (BPA) has imposed adverse effects on both ecosystems and human health. Herein, nanoporous MoS₂@BiVO₄ photoanodes were fabricated on fluorine-doped tin oxide (FTO) substrates for photoelectrocatalytic degradation of BPA. The photocurrent density of the optimized photoanode (MoS₂-3@BiVO₄) was 5.4 times as that of BiVO₄ photoanode at 1.5 V vs. Ag/AgCl under visible light illumination, which was ascribed to the reduced recombination of photogenerated charge carriers of the well-designed hybrid structure. 10 ppm of BPA could be completely degraded in 75 min by MoS₂-3@BiVO₄ photoanode, with a bias of 1.5 V vs. Ag/AgCl and 100 mM of NaCl as the supporting electrolyte. The electron paramagnetic resonance (EPR) and free radicals scavenging experiments confirmed that chlorine oxide radical (•ClO) played a dominant role in the degradation of BPA. 14 intermediates were detected and identified during photoelectrocatalytic degradation of BPA by MoS₂-3@BiVO₄ photoanode and 3 pathways were proposed based on the above intermediates. The hybrid film exhibited high stability and reusability, and promising application potential in photoelectrocatalytic degradation of organic pollutants in aqueous solution.

Molecularly imprinted photoelectrochemical sensing based on ZnO/polypyrrole nanocomposites for acrylamide detection

A highly sensitive quenching molecular imprinting (MIP) photoelectrochemical (PEC) sensor was proposed to detect acrylamide (AM) by using the photoactive composite of ZnO and polypyrrole (PPy) as the PEC signal probe. ZnO, with high electron mobility, excellent chemical and thermal stability as well as good biocompatibility, was selected as the photoelectrically active material. A polypyrrole film was formed on the nanodisk ZnO by electrochemical polymerization, and the recognition site of AM was left on the surface of the PPy film by elution, enabling the specific detection of AM. The transfer of electrons will be hindered when AM is adsorbed on the ZnO/PPy nanocomposites surface, which results in the decrease of photocurrent signal. The proposed molecularly imprinted PEC sensor exhibits significant detection performance of AM in the range of 10-1 M-2.5 × 10-9 M with a LOD of 2.147 × 10-9 M (S/N = 3). The use of photoelectrochemical technology combined with molecular imprinting technology enables the PEC sensor to have excellent selectivity, superior repeatability, preferable stability, low cost, and easy construction, providing a new method for the detection of AM. The high recovery rate in the detection of real samples of potato chips and biscuits indicates that the proposed PEC sensor has potential in monitoring the emerging food safety risks.