A sensitive acetaminophen sensor based on Co metal–organic framework(ZIF-67)and macroporous carbon composite

The composite of zeolitic imidazolate frameworks(ZIF-67)and ordered macroporous carbon(OMC)was successfully synthesized via in situ growth from the OMC matrix.The ZIF67–OMC composite was verified by scanning electron microscopy(SEM)and transmission electron microscopy(TEM),powder X-ray diffraction(XRD)and electrochemical impedance spectroscopy(EIS)and then evaluated as a modified material for electrochemical sensor.Benefitting from the large surface area and enhanced conductivity of the ZIF67–OMC composite,ZIF67–OMC nanocomposite showed superior electrocatalytic performance toward acetaminophen(AP)oxidation.The redox reaction of AP underwent a quasi-reversible redox reaction with higher anodic current at ZIF67–OMC modified electrode compared with the bare glassy carbon electrode(GCE).In optimal condition,the ZIF67–OMC/GCE was stable,reproducible and had a linear range of 0.05–100 μmol·L^(-1) AP concentration,with the detection limit of 20 nmol·L^(-1)(signal-to-noise of S/N=3).In addition,the prepared sensing platform for the detection of AP was evaluated for the compound paracetamol tablets and urine samples.

Mo2C@3D ultrathin macroporous carbon realizing efficient and stable nitrogen fixation

Ammonia is a key feedstock of fertilizers for farming and convenient hydrogen carrier as an emerging clean fuel,but industrial ammonium production process,Haber-Bosch reaction,is an energy-intensive process,consuming 1%–2%of global energy and producing 3%global CO2.Electrochemical nitrogen reduction reaction(NRR)is one of the most promising routes to realize highly efficient NH3 production under ambient conditions.However,up to now,few precious-metal-free electrocatalysts with desirable catalytic performance have been explored.In this work,Mo2C nanodots anchored on three-dimensional ultrathin macroporous carbon(Mo2C@3DUM-C)framework is developed toward significantly enhanced nitrogen reduction reaction.Thanks to the special structural design of 3D ultrathin macroporous carbon and highly active and stable Mo2C toward N2 electrochemical reduction,the Mo2C@3DUM-C framework exhibits a high Faradaic efficiency of 9.5%for NH3 production at−0.20 V and the yield rate reaches 30.4µg h−1 mgMo2C−1.Further electrochemical characterizations reveal the enhanced electron transfer and increased electrochemical surface area in the 3D macroporous carbon framework.Moreover,the Mo2C@3DUM-C electrocatalysts hold high catalytic stability after long-term NRR test.The temperature-dependent yield rate of NH3 demonstrates that the activation energy of nitrogen reduction on the employed catalyst was calculated to be 28.1 kJ mol−1.Our proposed earth-abundant Mo2C@3DUM-C demonstrates an alternative insight into developing efficient and stable nitrogen fixation catalysts in acids as alternatives to noble metal catalysts.