NiCo-LDH coupled with 2D ZIF-derived Co nitrogen doped carbon nanosheet arrays as a self-supporting electrocatalyst for detection of formaldehyde.

Formaldehyde is susceptible to illegal addition to foodstuffs to extend their shelf life due to its antimicrobial, preservative and bleaching properties. In this study, a self-supporting "nanosheet on nanosheet" arrays electrocatalyst with core-shell heterostructure was prepared in situ by coupling NiCo layer double hydroxide with 2D ZIF derived Co-nitrogen-doped porous carbon on carbon cloth (Co-N/C@NiCo-LDH NSAs/CC). Co-N/C nanosheet arrays act as a scaffold core with good electrical conductivity, providing more NiCo-LDH nucleation sites to avoid NiCo-LDH agglomeration, thus having fast mass/charge transfer performance. While the NiCo-LDH nanosheet arrays shell with high specific surface area provide more active sites for electrochemical reactions. As an electrocatalytic sensing electrode, Co-N/C@NiCo-LDH NSAs/CC has a wide linear range of 1 μM to 13 mM for formaldehyde detection, and the detection limit is 82 nM. Besides, the sensor has been applied to the detection of formaldehyde in food samples with satisfactory results.