Synthesis of SiO2@MnCo2O4 core–shell nanorattles using layered double hydroxide precursors and studies on their peroxidase-like activity†
Abstract
The current work demonstrates a simple soft chemical approach to synthesize SiO2@MnCo2O4 core–shell nanorattles using SiO2@MnCo-LDH (layered double hydroxide) precursors. XRD analysis indicates the formation of MnCo2O4 nanoparticles (NPs) on SiO2 spheres. FESEM images show hierarchical flower-like MnCo2O4 NPs on the surface of the SiO2 spheres. TEM micrographs show the interstitial space between the core (SiO2) and the shell (MnCo2O4), indicating the core–shell nanorattle morphology of SiO2@MnCo2O4. BET adsorption–desorption isotherms of the SiO2@MnCo2O4 core–shell nanorattles indicate their mesoporous nature with high surface area. Optical studies indicate O2− → Mn2+ and O2− → Co3+ charge-transfer transitions and d–d transition in pure MnCo2O4 NPs and the SiO2@MnCo2O4 core–shell nanorattles. XPS measurements indicate the presence of Si4+, Mn2+, Co2+, Mn3+, Co3+, and O2− in the SiO2@MnCo2O4 core–shell nanorattles. The SiO2@MnCo2O4 core–shell nanorattles show paramagnetic and superparamagnetic behavior at 300 K and 5 K, respectively. After characterization, the SiO2@MnCo2O4 core–shell nanorattles were explored for peroxidase-like activity for the first time. The SiO2@MnCo2O4 core–shell nanorattles act as a peroxidase nanozyme and exhibit better peroxidase-like activity than pure MnCo2O4 NPs and horseradish peroxidase.