Facile synthesis of CeO2 decorated Ni(OH)2 hierarchical composites for enhanced electrocatalytic sensing of H2O2

Abstract

CeO₂–Ni(OH)₂ composites with hierarchical structures were synthesized via a facile one-pot hydrothermal method, which were constructed with Ni(OH)₂ nanosheets decorated with in situ formed CeO₂ nanoparticles on their surface. The composites were characterized by XRD, SEM, HRTEM, XPS, Raman spectroscopy, and electrochemical techniques. The results of nitrogen adsorption–desorption, electrochemical impedance spectroscopy, and amperometry demonstrated that CeO₂ and Ni(OH)₂ components of CeO₂–Ni(OH)₂ hierarchical architectures showed a synergistic contribution on the improvement of electrochemical activity toward H₂O₂. The oxidation current was linearly related to the H₂O₂ concentration from 0.5 μM to 1.2 mM. The sensor showed a high sensitivity of 4.5 μA μM⁻¹ cm⁻² with a lower detection limit of 0.035 μM (S/N = 3). Moreover, the sensor showed good selectivity, reproducibility and stability. These results demonstrated the feasibility of the synthetic strategy and the potential of the composites as a promising candidate for H₂O₂ sensing.