Echinus-like Cu-Mo2C/C yolk-shell composites for ultrasensitive detection of hydrogen peroxide

ABSTRACT Nanomolar electrochemical detection of hydrogen peroxide has been recently looking forward owing to its extensive applications. Herein, Cu-Mo2C/C material was simply prepared by in-situ pyrolysis of new 3-D covalent bimetallic-organic framework [Cu(Mo2O7)L]n [L: N-(pyridin-3-ylmethyl)pyridine-2-amine] crystals under N2/H2 atmosphere, which presented ultrasensitive detection to H2O2. The Cu-Mo2C/C composite displays unique echinus-like yolk-shell structure, and Mo2C/C nanosheets were also obtained from the above composite after copper removal by liquid phase etching. Subsequently, the two composites were modified to the surface of glassy carbon electrode (GCE) by simple drop-coating, and the non-enzymatic electrochemical sensors were successfully fabricated. Cu-Mo2C/C/GCE presents prominent electrocatalytic H2O2 properties with high sensitivity of 392.7 μA•mM−1•cm−2 and wide detection range of 0.12 μM∼2.57 mM. The limit of detection (LOD) can be as low as 40 nM, which is 3.2 times larger than that of Mo2C/C/GCE. Such remarkable ultrasensitive H2O2 performance is mainly ascribed to the unique microstructure of Cu-Mo2C/C composite, platinum-like Mo2C, as well as copper and carbon co-doped. In addition, the Cu-Mo2C/C/GCE sensor has been successfully utilized to the detection of H2O2 in spiked human serum. The satisfactory results indicate that this electrode material has certain potential applications in the fields of biology and food.