This work focuses on the colloidal synthesis and electrochemical evaluation of nanocrystalline first-row transition metal oxides, including spinel, rock salt, and core–shell structured materials. These oxide systems, composed of earth-abundant elements, offer a low-cost and stable alternative to platinum group metal (PGM) catalysts for use in alkaline energy devices. While spinel oxides are known for their structural tunability and redox-active frameworks, rock salt phases provide distinct cation environments and potentially improved electrical conductivity. Core–shell architectures further enable control over interfacial properties, allowing separate optimization of catalytic activity and stability. Colloidal synthetic methods were employed to access these materials with tunable composition, phase, and morphology. The resulting nanocrystals were evaluated for their performance in the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), which are the primary kinetic limitations in alkaline electrolyzers and fuel cells, respectively. Special attention was given to multi-metal and high-entropy compositions, as well as interface-controlled structures, to study how cation distribution, crystal structure, and nanoscale architecture affect catalytic behavior. These findings contribute to a broader understanding of how structural motifs such as spinel, rock salt, and core–shell configurations influence oxygen electrocatalysis in alkaline environments and highlight the potential of colloidal approaches for designing low-cost, efficient materials for renewable energy conversion and storage technologies.