Electrocatalytic advancements with trimetallic nanoparticles: design strategies and roadmap.

Trimetallic nanoparticles (TMNPs) have emerged as a versatile class of nanomaterials whose multifunctional and synergistic properties surpass those of mono- and bimetallic systems. This review examines the recent advancements in TMNP synthesis, bridging conventional top-down techniques with state-of-the-art bottom-up strategies that provide precise control over atomic ordering while addressing concerns related to sustainability. This review provides a systematic discussion of the structural and synthetic innovations resulting in their rapid adoption in electrochemical applications, including fuel cells, oxygen and hydrogen electrocatalysis, supercapacitors, and electrochemical sensing. Particular emphasis on the influence of interfacial and compositional engineering in TMNPs, ameliorating superior catalytic activity and stability over conventional catalysts, has been comprehensively highlighted. Finally, key challenges, including scalability, long-term stability, biocompatibility, and miniaturization, have been outlined for future opportunities for designing sustainable, application-oriented TMNPs. By linking fundamental structure-property relationships with electrochemical performance, this review contributes a unified framework for fabricating next-generation TMNPs towards energy conversion, catalysis, and advanced sensing applications.