ZIF-9-Derived Cobalt and Nitrogen-Doped Carbon Nanocomposites for Sensitive Electrochemical Nitrite Determination

TL;DR

Researchers created a highly sensitive sensor for detecting nitrite using a carbon material derived from ZIF-9, which offers excellent performance and stability.

Contribution

A novel electrochemical sensor using ZIF-9-derived cobalt and nitrogen-doped carbon with optimized calcination temperature for nitrite detection.

Findings

The sensor achieved a detection range of 0.2–7000 μM with a sensitivity of 848.6 μA mM−1 cm−2.

It had a low detection limit of 50 nM and retained over 80% of its initial response after extended storage.

The material's performance is attributed to its graphitization degree, surface area, and active cobalt sites.

Abstract

The accurate monitoring of nitrite levels is critically important for safeguarding public health and ensuring food safety, as excessive intake presents severe risks. In this study, we developed a highly sensitive electrochemical sensor for nitrite detection utilizing a cobalt-embedded porous carbon material derived from zeolitic imidazolate frameworks (ZIFs) of ZIF-9. The precursor was subjected to pyrolysis at various temperatures, revealing that the sample carbonized at 800 °C (ZIF-9-800) exhibited superior electrocatalytic performance. This enhancement is attributed to its optimized graphitization degree, high specific surface area, and the well-dispersed active sites resulting from the in situ generated cobalt nanoparticles. The ZIF-9-800-based sensor demonstrated outstanding electrochemical performance, achieving a broad linear detection range of 0.2–7000 μM, high sensitivity (848.6 μA mM−1 cm−2), and an impressively low detection limit of 50 nM. Furthermore, the sensor exhibited excellent selectivity in the presence of common interfering ions and remarkable long-term stability, maintaining more than 80% of its initial response after extended storage. This work underscores the effectiveness of MOF-derived carbon-based catalysts, tailored through calcination temperature optimization, for constructing advanced electrochemical sensing platforms.

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