• • TMNs exhibit noble metal-like electronic structures and high conductivity, enabling comparable electrocatalytic activity to Pt, Ir, and Ru at a fraction of the cost, as evidenced by their use in HER, OER, and ORR.
• • Synthetic strategies such as direct nitridation, solid-state reaction, sol-gel assisted reaction, and wet-chemical reaction allow precise control over composition, dimension, size, and morphology, which directly influences active site density and charge transfer kinetics.
• • The insertion of N atoms into transition metal lattices increases metal-metal distances and downshifts the d-band center, optimizing adsorption energies of intermediates and boosting catalytic performance.
• • TMNs maintain structural and chemical stability in strong acid and alkaline conditions, making them suitable for durable operation in fuel cells, water electrolyzers, and metal-air batteries.