Sonochemically synthesized mesoporous cobalt oxide nanoparticles for luminol-enhanced chemiluminescence sensing

In recent years, mesoporous cobalt oxides have attracted more attention due to their exceptional physical and chemical properties and their important applications in various fields. The synthesis of cobalt oxides of various sizes, morphologies, and porosity is still a challenging process. In this report, mesoporous Co 3 O 4 NPs with different porosity were synthesized through facile, one-step, and cost-effective routes, without using any complicated materials or instruments, via the sonochemical process. X-ray powder diffraction (XRD), BET, and transmission electron microscopy (TEM) were used to characterize the as-synthesized NPs. XRD technique was used to determine the crystal structure and phase of the NPs, BET to describe the porous nature of the NPs, and TEM to investigate the structure and morphology of the NPs. Next, the effect of as-synthesized Co 3 O 4 NPs as a catalyst for the luminol-H 2 O 2 chemiluminescence system was studied. Co 3 O 4 NPs were chosen since they have nanoscale size, high specific surface area, and mesoporous nature. Therefore, these NPs can form more active sites and thus show unique catalytic activity than common ionic catalysts such as Co 2+ , Fe 3+ , Cu 2+ used in the luminol-H 2 O 2 CL system. Finally, this system was used to detect and measure H 2 O 2 and glucose under optimal conditions. A good linear relationship was observed between the chemiluminescence intensity of the designed system and the concentration of H 2 O 2 and glucose. A linear range like 0.25–10 pM for H 2 O 2 and 1–30 nM for glucose was obtained. The excellent LOD of the proposed method for measuring H 2 O 2 was about 0.07 pM, and for measuring glucose was about 0.14 nM.