Porphyrin-based metal–organic framework thin films for electrochemical nitrite detection

• Zirconium-based porphyrin MOF thin films are grown on conducting substrates.
• The MOF-525 thin film shows electrocatalytic activity for nitrite oxidation.
• Redox and electrocatalytic mechanisms of the MOF thin film are investigated.
• The amperometric nitrite sensor using MOF-525 thin film is successfully developed.

Uniform zirconium-based porphyrin metal–organic framework (MOF-525) thin films are grown on conducting glass substrates by using a solvothermal approach. The obtained MOF-525 thin film is electrochemically addressable in aqueous solution and shows electrocatalytic activity for nitrite oxidation. The mechanism for the electrocatalytic oxidation of nitrite at the MOF-525 thin film is investigated by cyclic voltammetry. The redox mechanism of the MOF-525 thin film in the KCl aqueous solution is studied by amperometry. The MOF-525 thin film is deployed as an amperometric nitrite sensor. The linear range, sensitivity, and limit of detection are 20–800 μM, 95 μA/mM-cm2, and 2.1 μM, respectively.

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