Nickel oxide nanoflakes decorated laser-induced porous graphene: An efficient electrochemical sensor for Paraquat and heavy metals

Abstract

The development of electrochemical sensing platforms capable of addressing environmental monitoring applications remains a significant challenge. Herein, we report a NiO nanoflakes decorated laser-induced porous graphene (NiO-LIG) electrode fabricated via a facile CO2 laser writing strategy. The laser writing enables in-situ transformation of hydrothermally synthesized NiO, from microscale flakes into uniformly distributed NiO nanoflakes on porous graphene. As an electrochemical sensor, the NiO-LIG electrode demonstrates excellent electrochemical sensing capability for paraquat (PQ), with a linear response in the range of 1-12 mu M and detection limit as low as 50 nM. Additionally, it shows highly sensitive toward heavy metal ions (Cd2+ and Pb2+), achieving linear detection over 1-10 mu M, and low detection limits of 7.8 nM and 7.5 nM, respectively. The NiOLIG electrode demonstrates high reproducibility, selectivity, and stability, and is successfully applied for real sample analysis in rice wash water and milk powder with recoveries close to 100%. This work presents a scalable and versatile approach for designing integrated electrochemical sensing systems, offering a unified platform for environmental and food safety applications.