Crafting Resilient Electrocatalysts: Tailoring Spinel Cobaltite Morphologies toward Alkaline Water Electrolysis

By systematically tailoring the morphology, the intrinsic catalytic properties of the materials can be fine-tuned, leading to improved activity with long-term stability. This study investigates the morphological evolution of nickel cobaltite-based materials, transitioning from 3D nanospheres of NiCo2O4 (NCO) to 2D nanoflakes of NiCo2S4 (NCS) and NiCo2Se4 (NCSe) layers and further to 1D nanotubes of NiCo2Te4 (NCTe). These NCTe nanotubes exhibit exceptional bifunctional catalytic performance, achieving a cell potential of 1.86 V to deliver 50 mA/cm2 in 1 M KOH with a commercial anion exchange membrane (AEM), and the purity of the evolved gases was analyzed using gas chromatography. This study emphasizes the vital role of morphology control in catalyst design, demonstrating its impact on active site optimization, surface area enhancement, and overall catalytic efficiency. This study integrates a robust experimental framework with theoretical insights obtained from first-principles density functional theory (DFT) calculations. A comparative work function analysis was performed for the (100) surface of 3d-transition-metal-based cobalt oxides to assess the catalytic efficiency of Ni-based compounds. The calculated work function of NCTe (4.1 eV) is lower as compared to that of Pt metal (5.6 eV) and RuO2 (5.2 eV) on the (100) plane, highlighting its potential as a viable catalyst. In addition to the geometrical effect of this compound, the lower work function facilitates efficient charge transfer, minimizes energy barriers, and enhances reaction kinetics, thereby improving catalytic activity and ensuring greater thermodynamic stability.