Novel neuron-network-like Cu-MoO₂/C composite derived from bimetallic organic framework for highly efficient...

Fabrication of non-enzymatic electrochemical sensors based on metal oxides with low valence-state for nanomolar detection of H₂O₂ has been a great challenge. In this work, a novel neuron-network-like Cu-MoO₂/C hierarchical structure was simply prepared by in-situ pyrolysis of 3D bimetallic-organic framework [Cu(Mo₂O₇)L]_n [L: N-(pyridin-3-ylmethyl)pyridine-2-amine] crystals. Meanwhile, the MoO₂/C nano-aggregates were also obtained by liquid phase copper etching. Subsequently, two non-enzymatic electrochemical sensors were fabricated by simple drop-coating of the above two materials on the surface of glassy carbon electrode (GCE). Electrochemical measurements indicate that the Cu-MoO₂/C/GCE possesses highly efficient electrocatalytic H₂O₂ property during wider linear range of 0.24 μM-3.27 mM. At room temperature, the Cu-MoO₂/C composite displays higher sensitivity (233.4 μA mM^-1 cm^-2) and lower limit of detection (LOD = 85 nM), which are 1 and 2.5 times larger than those of MoO₂/C material, respectively. Such excellent ability for trace H₂O₂ detection mainly originates from the synergism of neuron-network-like structure, enhanced electrical conductivity and increased active sites caused by low valence-state MoO₂ and co-doping of Cu and carbon, and even the interaction between Cu and Mo. In addition, the H₂O₂ detection in spiked human serum and commercially real samples indicates that the Cu-MoO₂/C/GCE sensor has certain potential application in the fields of environment and biology.