Enzyme-free Electrochemical Detection of Hydrogen Peroxide Based on the Three-Dimensional Flower-like Cu-based Metal Organic Frameworks and MXene Nanosheets†

Main observation and conclusion Cu-based metal organic frameworks (MOFs) are regarded as promising sensing materials, which have abundant metal sites, large surface area and simple synthesis processes. In this work, a novel three-dimensional flower-like Cu-MOF was synthesized, which was combined with ultra-thin MXene nanosheets to construct a novel electrochemical sensor for H2O2. During the electrocatalytic reduction of H2O2, the catalytic activity of Cu-MOF/MXene/GCE results in the ultra-sensitive detection of H2O2 owing to the structure properties of MOFs, the nature of Cu-contained nanomaterials as well as the high electrical conductivity of MXene. The Cu-MOF/MXene/GCE showed a wide linear range from 1 mu mol/L to 6.12 mmol/L using chronoamperometry at the detection potential of -0.35 V, and the detection limit is estimated to be 0.35 mu mol/L. The sensor also shows good anti-interference due to the lower detection potential, specific catalysis of Cu-MOF to H2O2, which promises the sensor good selectivity in complexed samples. Meanwhile, the electrochemical sensor is capable to detect H2O2 in milk and serum samples with satisfactory recoveries. The ultra-sensitivity, rapid detection, and easy operation of the proposed sensor present significant prospect for real-time analysis and monitoring of H2O2 in foods and biological samples.

Automated summary

Cu-based metal organic frameworks are promising sensing materials due to their abundant metal sites and large surface area. The novel Cu-MOF/MXene/GCE electrochemical sensor showed ultra-sensitive detection of H2O2 with a wide linear range and low detection limit, as well as good anti-interference and selectivity in complex samples. The sensor also demonstrated satisfactory recoveries for detecting H2O2 in milk and serum samples, presenting significant prospects for real-time analysis and monitoring in foods and biological samples.