Vertical growth of leaf-like Co-metal organic framework on carbon fiber cloth as integrated electrode for sensitive detection of dopamine and uric acid

Application of metal organic framework (MOF) in electrochemical sensors usually suffer from poor conductivity, low electrocatalysis, material aggregation and complex electrode fabrication. Here, leaf-like Co-MOF (L-Co-MOF) vertically grown on carbon cloth (CC) was prepared as integrated electrode for electrochemical detection. The L-Co-MOF/CC with interlaced Co-MOF nanosheets as building blocks greatly reduces aggregation, provides large surface area and highly exposed active sites to interact with analyte. The synergy between L-Co-MOF and CC endows the composite greatly enhanced electrocatalysis on oxidation of dopamine (DA) and uric acid (UA) compared with those of ordinary polyhedral Co-MOF or 2D Co-MOF grown in solution. The L-Co-MOF/CC can be directly used as working electrode without further modification, and it achieved the separate detection of DA and UA in the range of 5.6 nM-70 μM, and 21 nM-350 μM, respectively. Simultaneous detection of DA and UA was also performed with a LOD of 2.5 nM for DA and 7 nM for UA, respectively. The sensor with high reproducibility and good anti-interference properties also achieved practical sensing of DA and UA in serum with recoveries of 83.3–104.0%. Such integrated 2D-MOF-carbon material composite with unique structure and high electrocatalysis hold great promise in electrochemical device.