Nickel oxide doped ceria nanoparticles (NiO@CeO2) for boosting oxygen evolution reaction and enhancing stability

Abstract

Electrochemical water electrolysis for the production of H2 and O2 is an extremely important and attractive technology that mainly depends on efficient and affordable electrocatalysts. However, the sluggish kinetics of OER is the main obstacle in water electrolysis. In this work, we have fabricated hybrid electrocatalysts based on CeO2 and NiO nanomaterials by varying the concentration of NiO to boost OER activity and stability. CeO2 and NiO nanomaterials were synthesized using [(NH4)2 Ce(NO3)6] and [Ni(NO3)2·6H2O] as precursors, respectively. All the prepared electrocatalysts namely NiO, CeO2, 10-NiO@CeO2, 20-NiO@CeO2, 30-NiO@CeO2, and 40-NiO@CeO2, were well characterized by various analytical tools to evaluate their morphologies, phases, crystallinities, compositions and electrochemical activities. Among the series of fabricated electrocatalysts, 20-NiO@CeO2 appeared as an efficient electrocatalyst with a very low overpotential of 392 mV to reach 50 mAcm−2 current density. In addition, a lower value of the Tafel slope, as measured from the curve of linear sweep voltammetry (LSV), indicates better OER kinetics. Furthermore, the charge transfer resistance (Rct) and electrochemical active surface area (ECSA) were measured, which further supports the excellent OER performance of 20-NiO@CeO2. These findings pave the way toward the rational design of bimetallic electrode materials for excellent OER activity.