Ultrafine Co3O4 Nanoparticle-Loaded Carbon Spheres for the Simultaneous Ultrasensitive Electrochemical Determination of Hydroquinone and Catechol

Owing to their toxicity, highly sensitive detection of the two main dihydroxyphenyl isomers of hydroquinone (HQ) and catechol (CC) is of great significance for environmental monitoring. In this work, a novel strategy has been developed to prepare ultrafine Co3O4 nanoparticle-loaded carbon spheres (Co3O4/CSs) as high-performance electrochemical sensing materials for the simultaneous determination of HQ and CC. Ultrafine Co3O4 nanoparticles were formed and uniformly decorated on the surface of carbon spheres through pyrolyzing cobalt phthalocyanine (CoPc) adsorbed on carbonaceous spheres (carbonaceous sphere@CoPc) in an inert nitrogen environment. Electrochemical measurements revealed that the Co3O4/CSs-modified glassy carbon electrode (GCE) exhibited excellent responses toward HQ and CC capability. The obtained detection limits of HQ and CC were as low as 2.6 and 3.4 nM, respectively. Simultaneous analysis of HQ and CC with high repeatability and anti-interference has also been demonstrated, fundamentally preserving their individual sensitivity without any interference. The high sensitivity and selectivity toward HQ and CC have been further discussed in combination with the special structure and composition of Co3O4/CSs. Additionally, the practicality of the Co3O4/CSs electrochemical sensor was evaluated, with satisfactory results in real water samples.