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[Display omitted] • The hierarchical SnO 2 /CC was designed and synthesized for IDP detection. • The in situ derivatization strategy was proposed in this paper. • SnO 2 /CC created the structural advantage to improve catalytic activity. • SnO 2 /CC exhibits favorable electrocatalytic reduction performance for IDP. Designing sensitive and rapid sensing platforms for detection of pesticide residues is essential for food safety. Herein, we designed and synthesized the hierarchical SnO 2 nanoparticles on carbon cloth (SnO 2 /CC) for the electrochemical detection of imidacloprid (IDP) based on in situ derivatization strategy. The hierarchical structure of SnO 2 /CC can maintain the original nanosheet morphology of SnS 2 and prevent the aggregation of SnO 2 nanoparticles, which endows SnO 2 /CC with a large specific surface area, abundant active sites, and fast electron transfer, which is beneficial to improve its electrocatalytic performance. Electrochemical studies showed that SnO 2 /CC exhibited favorable sensing performance for IDP under optimized conditions, including a linear range of 0.5–60 μM, extremely high sensitivity of 60.88 μA μM−1 cm−2, and a low detection limit of 0.056 μM. Additionally, the electrode was verified to have satisfactory feasibility by detecting IDP in grape and apple samples. This work opens a new perspective for the fabrication of high-performance IDP electrochemical sensors based on hierarchical nanostructured metal oxide. [ABSTRACT FROM AUTHOR]

Developing electrode materials with excellent electrocatalytic properties for detecting pesticide residues plays a vital role in the safety of agricultural products and environmental applications. Herein, we designed a new electrochemical sensor on the basis of N-doped carbon hollow nanospheres modified with Sn/MoC Schottky junction (Sn/MoC@NC) for methyl parathion (MP) detection. The Sn/MoC@NC was prepared by self-assembled polymerization-anchoring strategy and high-temperature carbonization design. Sn/MoC Schottky junction and hollow nanosphere structure endow Sn/MoC@NC with a larger surface area, more active sites, and faster electron transfer, which is beneficial to enhancing its electrocatalytic performance. The structural characterizations and physicochemical properties of Sn/MoC@NC were explored through various microscopy, spectroscopic and electrochemical techniques. The experimental results confirmed that the calibration curve for current and MP concentration (0.05–10 μg/mL) was available under optimized conditions, and the sensitivity and detection limit were respectively determined to be 9.02 μA μM 1 cm 2 and 8.9 ng/mL. Furthermore, the constructed sensor displayed excellent selectivity, repeatability, and stability, which qualified it for use in detecting MP in grapes and tap water with satisfactory recovery. This work may provide some interesting prospects for constructing high-performance electrocatalysts for MP detection. [Display omitted] • Sn/MoC@NC Schottky catalyst was designed and synthesized for MP detection. • The self-assembled polymerization-anchoring strategy was proposed in this paper. • The coupling of of Schottky junction and nano hollow improve catalytic activity. • Sn/MoC@NC/GCE exhibits superior electrocatalytic reduction performance for MP. [ABSTRACT FROM AUTHOR]

[Display omitted] • Double-deck petal-like Z-NiO/CoO@CC was synthesized for MP detection. • Etching-doping sedimentation were used to introduce Ni element and keep feature. • Bimetal oxides in carbon nano-frame (ZIF-67 derived) improve catalytic activity. • The Z-NiO/CoO@CC shows the satisfying performance towards MP detection. • The mechanism for MP detection were revealed clearly. Designing efficient and rapid methods for detection of pesticide residue is one of the prerequisites to reduce its negative health influences. Herein, we constructed an electrochemical sensor for efficient detection of Methyl parathion (MP) using a double-deck petal-like NiO/CoO nanoporous carbon composite (Z-NiO/CoO@CC). The Z-NiO/CoO@CC was fabricated through etching-doping sedimentation strategy and carbonized conversion. The elaborate electrocatalyst not only created the structural advantages to offer more activities sites for the target analyte, but also had compositional virtues by combining the carbon nano-frame (originating from zeolitic imidazolate framework, ZIF-67) and bimetal oxides to enhance electrochemical performances. Besides, the electro-catalysis mechanism and detection performance of the prepared electrode were also detailly studied through different electrochemical techniques. Under optimized conditions, the prepared Z-NiO/CoO@CC showed favorable performance for MP detection with linear range from 10 ng/mL to 10 μg/mL, high sensitivity of 12.8 μA μM−1 cm−2 and low detection limit of 3.6 ng/mL (S/N = 3). Moreover, the practical feasibility of the Z-NiO/CoO@CC was also verified through monitoring MP in tap water and grape samples. This work has explored a novel method for construction of high-performance electrochemical MP sensors. [ABSTRACT FROM AUTHOR]

• Bimetallic-MOF-derived crystalline–amorphous interfacial sites were designed. • The sufficient contact of the two phases maximizes the synergistic effect. • The systematic optimization of charge transfer promotes the nitrite detection kinetics. • The developed sensor has been successfully used in food samples for nitrite detection. Considering the importance of rapid and effective detection of nitrite in food samples, herein, we report a multistep heterophase synthetic strategy for constructing crystalline–amorphous zinc/cobalt iron porous nanosheets (C-A Zn/Co-Fe PNSs) on carbon cloth. Notably, the C-A Zn/Co-Fe PNSs@CC electrochemical interface consists of interlaced carbon fibers with many uniformly distributed hybrid nanosheets containing crystalline-amorphous interfacial sites. This particular hybrid structure permits local enrichment of nitrite for enhanced nitrite capture efficiency, laying a solid foundation for the ultrasensitive detection of nitrite. In proof-of-concept experiments, we verified that C-A Zn/Co-Fe PNSs@CC could be used to analyze nitrite with good sensitivity and reproducibility. It is worth mentioning that an ultra-low LOD of 0.44 μM was obtained for the detection of nitrite. The designed electrochemical sensor worked well in complex samples such as sausages and tap water under optimal parameters. [ABSTRACT FROM AUTHOR]

Excessive residues of nitrofurantoin (NFT) can cause serious contamination of water bodies and food, and potential harm to ecosystems and food safety. Given that, rapid and efficient detection of NFT in real samples is of particular importance. MoS 2 is a promising electrochemical material for this application. Here, MoS 2 was modulated by Metal-organic framework through the interfacial microenvironment to enhance the catalytic activity and carbonized to form Co 2 Mo 3 O 8 nanosheets with high electrical activity. The resulting Co 2 Mo 3 O 8 /MoS 2 hybrid structure can be used to prepare highly sensitive NFT electrochemical sensor. The Co 2 Mo 3 O 8 /MoS 2 @CC electrochemical sensor exhibits strong electrochemical properties due to its fast electron transfer, excellent electrical conductivity, abundant defect sites, and high redox response. Based on this, this electrochemical sensor exhibited excellent electrocatalytic activity for NFT with a wide linear detection range, low detection limit, and high sensitivity. Moreover, the electrode was successfully applied to detect NFT in milk, honey, and tap water, strongly confirming its potential in real samples. This work could furnish the evidence for interfacial microenvironmental regulation of MoS 2 , and also offer a novel candidate material for NFT sensing. [Display omitted] • The sensor with rich Co2Mo3O8/MoS2 hybrid structure were fabricated. • Highly electroactive Co2Mo3O8 nanosheets are formed by carbonization reduction. • Interfacial microenvironment modulation can improve the catalytic activity of MoS2. • Efficient electrocatalytic reduction of NFT is achieved on Co2Mo3O8/MoS2@CC sensor. [ABSTRACT FROM AUTHOR]

• The MoO 3 /Co 3 O 4 heterostructure was formed via a hybrid electrochemical deposition strategy. • The synergistic effect of Co 3 O 4 and MoO 3 plays a predominant role in nitrite electrooxidation. • The MoO 3 /Co 3 O 4 /CC has been successfully used in food samples for nitrite detection. Considering excess nitrites are detrimental to the human body and environment, designing a rapid, sensitive, and real-time quantitative determination for nitrite is of great significance for environmental preservation and public health. In this paper, Co 3 O 4 nanoflowers coupled with ultrafine MoO 3 nanoparticles (MoO 3 /Co 3 O 4) are obtained via a hybrid electrochemical deposition strategy (HED). The as-designed MoO 3 /Co 3 O 4 /CC integrating electrode exhibits superior electrocatalytic properties towards nitrite oxidation, owing to the synergistic effect between MoO 3 and Co 3 O 4 caused by the heterostructure of MoO 3 /Co 3 O 4. The electrode achieved a low response time of 2 s, an excellent sensitivity of 1704.1 μA mM−1 cm−2, and a low limit of detection of 0.075 μM (S/N = 3). Furthermore, the electrode displays promise for nitrite detection in complex food such as water and sausages samples. Our study will provide a significant strategy for the application of bimetallic heterostructure to explore the design of sensing interfaces. [ABSTRACT FROM AUTHOR]

Electrochemical analysis enables pesticides monitoring become rapid and efficient. Herein, novel three dimensional nitrogen–doped macro–meso–microporous carbon composites (N/Cu–HPC) derived from polyvinylpyrrolidone (PVP) doped Cu–metal organic framework were successfully formed via one–pot solvothermal method followed by pyrolysis, which were further applied in high–performance electrochemical determination of neonicotinoid. The introduction of PVP endows the N/Cu–HPC good hydrophilicity preventing aggregation as well as more highly electronegative nitrogen species boosting electro–catalytic property dramatically. Interestingly, the macro–meso–microporous architecture improves mass and charge transports between neonicotinoid molecules and active sites such as Cu nanoparticles and carbon atoms possessing Lewis basicity next to pyridinic-N. Based on the N/Cu–HPC, imidacloprid (IDP), thiamethoxam (THA) and dinotefuran (DNF) were detected with wide linear detection ranges (0.5–60 μM for both IDP and DNF, 1–60 μM for THA) and low detection limits (0.026 μM for IDP, 0.062 μM for THA and 0.01 μM for DNF). Meanwhile, this sensor can be successfully used for determination of IDP, THA and DNF in oat, corn and rice with good recoveries (92.0–100.9%, RSD ≤ 4.8%), demonstrating that the N/Cu–HPC possesses a high potential to be an advanced sensing device for monitoring neonicotinoid in agricultural products. [Display omitted] • 3D hierarchical porous N/Cu-HPC was successfully constructed via PVP-assisted strategy followed by pyrolysis. • Hydrophilicity and N species of N/Cu-HPC prevent aggregation as well as boost electro-catalysis performance. • The macro–meso–microporous architecture dramatically enhances mass diffusion of target molecules. • Imidacloprid, thiamethoxam and dinotefuran were sensitively detected using N/Cu-HPC. • The electrochemical reaction mechanisms toward neonicotinoid were systematically revealed. [ABSTRACT FROM AUTHOR]