Two is superior to one: Bi-metallic low-nuclearity catalysts for advanced catalytic applications

• Bimetallic SACs deliver enhanced catalytic activity via synergistic effects. • Inter-metallic interactions enable modulation of the electronic and geometric properties. • Bifunctional catalytic sites facilitate concerted mechanisms in multi-step reactions. • Design precision, long-term stability avoiding deactivation are key challenges. Catalysis is a fundamental pillar of modern society driving innovations across organic, inorganic, physical, and industrial chemistry. Noble metal catalysts have traditionally led the field, but rising energy demands and sustainability concerns call for new approaches. Bimetallic single-atom catalysts (bim-SACs) are emerging as a revolutionary class of materials promising high activity and selectivity through effective, low-energy reaction pathways. In this review, we provide an analysis of the structure, function, and catalytic applications of bim-SACs, emphasizing their essential role where their tailored atomic architectures address critical energy, environmental, and industrial hurdles. Harnessing the synergistic interplay of neighboring metal atoms, bim-SACs surpass the limitations of traditional catalysts, unlocking electronic and geometric synergies that amplify reactivity, selectivity, and stability. From enabling green hydrogen production to decarbonization of chemical synthesis, bim-SACs have already made substantial contributions and promise to epitomize the fusion of atomic precision and functional versatility. Their intricate electronic structures set them apart from traditional catalysts, thereby revolutionizing catalytic efficiency. This review explores the multifaceted applications of bim-SACs in electrocatalysis, photocatalysis, and thermocatalysis, highlighting their potential to pioneer sustainable technologies for a resource-conscious world. As the field evolves, bim-SACs represent a paradigm shift, offering a promising avenue for next-generation catalytic innovations, where atomic-level engineering propels global technological advancement.