Synthesis of 3D mesoporous samarium oxide hydrangea microspheres for enzyme-free sensor of hydrogen peroxide

A novel 3D mesoporous Sm₂O₃ hierarchical hydrangea microspheres sensor has been developed and investigated for highly sensitive electrochemical detection of hydrogen peroxide (H₂O₂). Their morphology and structure were observed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) isotherms and the Barret-Joyner-Halenda (BJH) measurements. This stable non-enzymatic sensor was found to capable of implementing H₂O₂ detection in a wide linear range from 1 to 320 μM with a linear correlation coefficient (R) of 0.997. It presents an ultrahigh sensitivity of 20.5 μA mM^-1, a remarkably low detection limit of ∼1 μM (signal/noise = 4), as well as a prompt response attaining 95% of steady current within 3 s. As such, the Sm₂O₃ hierarchical hydrangea microspheres are considered one of the remarkably prominent sensors for the detection of hydrogen peroxide in biological diagnosis, food and environmental monitoring.