Ternary NiFeCo-glycerolate catalysts: rational design for improved oxygen evolution reaction efficiency

Abstract

Catalysts capable of overcoming the bottleneck of water splitting, known as the oxygen evolution reaction (OER), are indispensable to the expansion of renewable energy systems. Thus, we report the synthesis of ternary glycerolate containing Ni, Fe, and Co metals by an easy one-pot solvothermal method. Interestingly, the iron precursor content plays a key role in the formation of microspheres, as confirmed by scanning electronic microscopy (SEM) images. In fact, when Fe-acetate precursor content exceeds 33.3% in molar proportions, particles without a defined morphology are generated. By comparing three distinct compositions of Ni_1−2xFe_xCo_x-Gly (x = 0.2; 0.3; 0.33, respectively), the best performance is achieved with Ni_0.4Fe_0.3Co_0.3-Gly, showing an excellent overpotential of 277 mV and a Tafel slope of 36.24 mV dec⁻¹. The presence of in situ formed metal oxyhydroxide species on the electrode surface is the key to the high-performance catalyst presented in this work. Where the interaction between Ni^2+/3+, Fe^2+/3+, and Co^2+/3+ provides significant electroactivity under OER conditions over 16 h at 10 mA cm⁻², with a positive potential shift of 19 mV in alkaline medium (1 M KOH). These findings highlight the potential of NiFeCo-Gly catalyst as an efficient material for OER in renewable energy applications.