Faming Gao

Sensitive detection of organophosphorus pesticides (OPs) is essential for food safety and environmental protection. Here, an AChE@HMUiO66(Ce)-Zn@Au composite nanoreactor was constructed as an electrochemical sensing interface for OP detection in complex samples. The defective hollow mesoporous UiO66(Ce) (HMUiO66(Ce)) framework provides accessible sites and a confined microenvironment for acetylcholinesterase (AChE) immobilization. Zn2+ modulates the local coordination environment to support enzyme immobilization, while Au nanoparticles (AuNPs) facilitate interfacial electron transfer. The immobilized AChE exhibits a low apparent Michaelis constant (Km) of 0.224 μM, indicating high apparent substrate affinity. The biosensor shows linear responses over 1.20 × 10-13–1.20 × 10-6 M for malathion and 5.40 × 10-14–5.40 × 10-6 M for chlorpyrifos, with detection limits of 2.15 × 10-15 and 1.95 × 10-15 M, respectively. It also exhibits good stability and resistance to interference from common inorganic ions and small organic molecules. Analysis of real samples further supports its reliability for OPs detection in food safety and environmental monitoring.

Selective nitrate-to-ammonia electroreduction requires efficient NO3- activation together with productive use of surface reactive hydrogen (*H), which competes with hydrogen evolution. Here, we construct a Cu-enriched SnS/rGO heterostructure through a galvanic-redox process that reconstructs the SnS surface into electronically differentiated Cu-Sn/S environments. Cu LMM Auger spectra identify Cu0 and XPS shows concurrent Sn2+-Sn4+ oxidation, while XRD confirms retention of the bulk SnS lattice, placing the redox chemistry in the near-surface region. Calculations reveal charge accumulation on Cu, a work-function decrease from 4.42 to 3.75 eVand stronger NO3- binding , indicating that Cu makes neighbouring Sn sites energetically non-equivalent to their pristine counterparts. Cu/SnS-rGO achieves an NH3 Faradaic efficiency of 93.87 % at -0.8 V vs. RHE and a yield of 5900.8 μg h-1 mgcat-1 at -0.9 V, with 15N labelling confirming nitrate as the nitrogen source and performance retained over eight cycles and 20 h. Cyclic voltammetry reveals a larger *H reservoir that diminishes upon nitrate addition, and operando ATR-SEIRAS shows stronger *NHx signatures and a higher fraction of strongly hydrogen-bonded interfacial water. These results identify galvanic-redox-induced site differentiation as a testable interface design principle for limiting unproductive H2 formation during selective nitrate-to-ammonia conversion.

Efficient alkaline hydrogen evolution requires rapid water dissociation and onward migration of adsorbed hydrogen (H*), yet coordinating these sequential processes across metal–support interfaces remains challenging. Here, Ru clusters are anchored on oxygen-vacancy-rich WO3-x nanoneedle arrays (Ru/RWO), with lower-vacancy Ru/PWO as a control. Experiments and density functional theory calculations reveal that vacancy enrichment coordinates support-side water activation and subsequent H* migration. Vacancy-adjacent undercoordinated W centers act as Lewis acid sites, promoting H2O adsorption and O–H bond cleavage. Meanwhile, the reduced work-function mismatch weakens net electron withdrawal from Ru and alleviates interfacial charge accumulation, thereby mitigating excessive H* stabilization at interfacial Ru and lowering the barrier for onward migration to an adjacent Ru site within the cluster from 0.32 to 0.23 eV. Ru/RWO requires only 22 and 61 mV to deliver 10 and 100 mA cm-2, respectively, with a Tafel slope of 34.2 mV dec-1 in 1.0 M KOH, and sustains 0.5 A cm-2 for 600 h. An anion-exchange-membrane water electrolyzer reaches 1.0 A cm-2 at 1.91 V and operates for 150 h. These findings provide a coupled structural and electronic regulation strategy for synchronizing intermediate generation and transfer in multistep electrocatalysis.

Crystalline metal–organic framework (MOF) materials with well-ordered structures enable precise surface engineering and a high degree of reproducibility. Nevertheless, the inherent rigidity and stability of crystalline lattices make it difficult to generate abundant surface defects and active sites. Conversely, amorphous MOF materials feature short-range order architectures with numerous disordered regions, dangling bonds, sufficient active sites and defects, thereby positioning them as a promising alternative for advanced functional design. Herein, amorphous CeM-MOF (M = Ni, Mn, Co) with spindle-shaped nanosheet architecture was precisely synthesized via shear-driven kinetic trapping strategy and employed as an advanced sensing material. Compared with the crystalline MOF (cCeCo-MOF), the amorphous MOF (aCeCo-MOF) with larger electroactive surface area, enhanced electron transfer capacity, sufficient surface defects as well as immobilization sites for enzyme, collectively boost interfacial reaction kinetics and sensing performance. The constructed aCeCo-MOF-based sensor achieves ultra-low detection limits of 28 fM for methamidophos and 3.9 fM for methyl parathion. Furthermore, the platform’s practical applicability was validated by detecting pesticide residues in agricultural products and water samples with satisfactory recoveries of 93.4% ~ 107.1%. This rationally designed amorphous bimetallic MOF-based biosensor for ultra-sensitive monitoring of pesticides holds promise for future whole-chain rapid monitoring in food safety research.

Sensitive monitoring of organophosphate pesticide residues is critical for ensuring food safety and environmental protection. However, the analytical performance of enzyme-based electrochemical biosensors is often restricted by inefficient interfacial electron transfer and limited catalytic efficiency of immobilized enzymes. Herein, a hollow nanocage-structured metal-carbon composite derived from a Prussian blue analogue (CoFe/NC@C) is rationally engineered as a high-efficiency electrode interface to enable ultrasensitive electrochemical sensing. The designed nanocage architecture integrates highly dispersed Co7Fe3 alloy nanoparticles within a conductive carbon framework, generating a hierarchical porous structure with abundant active sites and charge-transport pathways. Such structural features not only provide a favorable microenvironment for acetylcholinesterase (AChE) immobilization but also significantly accelerate interfacial electron transfer and enzymatic catalytic reactions. Benefiting from the synergistic effects of the CoFe alloy nanoparticles, conductive carbon matrix, and hollow porous architecture, the constructed AChE-NF/CoFe/NC@C-t/GCE biosensor exhibits outstanding detection performance. The biosensor enables ultrasensitive detection of methamidophos and dichlorvos with detection limits as low as 1.16 × 10-13 mol/L and 6.97 × 10-14 mol/L, respectively, together with wide linear ranges and reliable performance in real sample analysis. This work constructs a nanocage-structured enzyme-based sensor for pesticide detection, providing new insights into the application of hierarchical metal-carbon nanostructures in biosensing.

A hierarchical Zn-substituted Fe3O4@NC/CuS@MoS2 heterostructure was rationally designed for the electrochemical detection of organophosphorus pesticides such as methamidophos and dichlorvos. Hollow Fe2O3 nanospheres were synthesized hydrothermally, followed by Zn-substitution, polydopamine-derived nitrogen-doped carbon coating, and in situ growth of CuS@MoS2 nanosheets. The Zn-substitution modulates the electronic structure, while the carbon network and the CuS@MoS2 heterojunction synergistically enhance charge transfer kinetics, increase the electroactive surface area, provide abundant sites for acetylcholinesterase immobilization, and ensure favorable biocompatibility. The resulting enhanced interfacial electron transfer reduces the charge transfer resistance to 41.6 Ω. The biosensor exhibits broad linear ranges for methamidophos (7.09 × 10–7 μM to 7.09 × 10–2 μM) and dichlorvos (4.53 × 10–7 μM to 4.53 × 10–2 μM), with detection limits of 8.7 × 10–8 μM and 2.0 × 10–7 μM, respectively. Real-sample analysis in Chinese cabbage and apple yields recoveries of 96.36%–102.40% for methamidophos and 95.92%–101.77% for dichlorvos, confirming its practical viability for trace pesticide monitoring.

Metal-organic frameworks (MOFs) provide an ideal confinement platform for enzyme immobilization. However, their intrinsically narrow microporous diffusion channels create severe mass transport limitations that significantly restrict the catalytic activity of encapsulated enzymes. Here, we report a hierarchical enzyme nanoreactor constructed via an interfacial reconstruction strategy triggered by hexacyanoferrate ([Fe(CN)₆]3-) ions, in which Prussian blue analogues (PBAs) are directly generated on a ZIF-67 scaffold preloaded with acetylcholinesterase (AChE). This transformation remodels the originally dense MOF into a hierarchically porous architecture, thereby generating a more favorable microenvironment that improves substrate diffusion and enzyme accessibility, ultimately leading to enhanced catalytic performance. Besides, PtNPs were introduced via in situ reduction to enhance conductivity, accelerate electron transfer, and further improve the sensitivity of the sensor. On this basis, the CS-AChE@ZIF-67@PBA4-Pt/GCE (CS-AZP4-Pt/GCE) biosensor was further constructed for the ultrasensitive determination of organophosphorus pesticides (OPs) and carbamate pesticides (CPs). The sensor exhibits wide linear ranges (3.60 × 10-13–3.60 × 10-6 M for monocrotophos and 1.24 × 10-12–1.24 × 10-6 M for carbaryl), ultralow detection limits (3.62 × 10-14 M and 5.78 × 10-13 M, respectively), along with excellent selectivity and operational stability. This study proposes a strategy to overcome diffusion limitations during enzymatic catalysis through interface reconstruction, offering a novel approach to the design of hierarchically structured nanoreactors for high-performance biosensing applications.

Reliable and sensitive monitoring of organophosphorus pesticide (OP) residues in tea is essential for food safety and public health protection. Despite their effectiveness, the performance of these electrochemical sensors based on acetylcholinesterase (AChE) is often limited by insufficient interfacial enrichment and slow charge transfer kinetics. In this study, hollow spherical nitrogen-doped porous carbon (HS-NC) derived from ZIF-8 was employed as an interfacial matrix for parathion-methyl (PM) detection. The hollow porous structure favours the immobilization of enzyme and molecular diffusion. The nitrogen speciation controls the interfacial adsorption and electron transfer. By combining experimental and theoretical analysis, distinct functionalities of different nitrogen configurations are revealed: pyridinic-N plays a dominant role in PM adsorption and interfacial pre-concentration, while graphitic-N contributes to charge transport in the conjugated carbon network. By benefiting from the synergistic interfacial regulation, the AChE-CS/HS-NC/GCE achieves a broad linear range and a low detection limit of 1.77 × 10-15 M toward PM. Furthermore, the biosensor shows good reproducibility, stability, selectivity, and reliability for real tea samples. This study presents a nitrogen-speciation-guided interface-engineering protocol to improve enzymatic electrochemical sensing, paving the way for new structure–function insights in heteroatom-doped carbon interfaces.

We demonstrate the fabrication of PtPdNiCuMnAu high‐entropy nanocages (HENCs) through a facile liquid‐phase reduction method followed by acid etching treatment. The multi‐component characteristic induces electron redistribution, which regulates the Pt d ‐band center with effect. The incorporation of Mn, endowed with distinct atomic size and coordination environment, introduces significant lattice distortion and atomic‐level defects. Trace Au plays a crucial role in elevating the vacancy formation energy, thus significantly suppressing elemental segregation under electrochemical bias. Additionally, the acid etching treatment further exposes abundant active sites as well as precisely tailors the adsorption kinetics of oxygen intermediates. Benefiting from these synergistic effects, PtPdNiCuMnAu HENCs exhibit a remarkable half‐wave potential ( E _1/2 ) of 0.925 V vs . RHE and a high mass activity (MA) of 1.70 A/mg _Pt . Furthermore, the catalyst displays exceptional electrochemical stability, with only a 4 mV negative shift in E _1/2 and a mere 5.6% loss in MA after 10, 000 accelerated durability test cycles. With this catalyst integrated, the membrane electrode assembly demonstrates a remarkable peak power density of 381.6 ± 3.10 mW/cm ² under H ₂ ‐O ₂ conditions, achieved at a back pressure of 2.0 bar and a cathode loading of 0.2 mg _Pt /cm ² .