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

Abstract

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.

Anion-exchange synthesis of an MnCo2S4 electrocatalyst towards facilitated ultralong hydrogen evolution reaction in acidic and alkaline media

“…12–15 Recent experimental and theoretical results showed that MnCo 2 O 4 catalyst demonstrated good redox properties, multiple valence states, outstanding mechanical robustness, higher intrinsic catalytic activity owing to larger catalytically active centers arising from the higher Co 3+ state, and modest binding proficiency towards the reactants (protons or atomic hydrogen and water molecules). 16–21 However, most of the reported processes can merely catalyze HER in alkaline or acidic media efficiently. 20,22 To boost the catalytic HER performance of MnCo 2 O 4 catalysts through the effective improvement of catalytic sites and conductivity for water dissociation by converting the catalyst into nitrides, phosphides, and/or sulfides.…”