From MOF membrane to 3D electrode: a new approach toward an electrochemical non-enzymatic glucose biosensor

A three-dimensional (3D) nickel oxide (NiO) catalytic electrode was fabricated by annealing Ni₂(L-asp)₂bipy MOF membrane and was subsequently applied for electrochemical glucose sensor. This 3D self-supported MOF membrane precursor provided uniform and porous architecture, and it was used for fabricating 3D NiO electrode in the first time. The SEM and XRD data showed that the NiO was evenly distributed on Ni mesh and complete transformation from Ni₂(L-asp)₂bipy to NiO. This catalytic electrode, using a chronoamperometric approach, demonstrated linear range up to 400 μM with high sensitivity of 478.9 μA mM⁻¹ cm⁻² and low limit of detection of 4.34 μM. Uric acid, urea and ascorbic acid showed negligible interferences to the detection of glucose. The excellent performance of this electrode was attributed to the uniformly distributed NiO on the Ni substrate, direct electron transformation from Ni substrate to electrochemical active NiO and the porosity of such electrode design.