Breaking the “Industrial Vitamin” Paradigm: La-N 4 Single-Atom Sites Enable Highly Active Multicomponent Electrochemical Sensing in Tear Fluid

Rare-earth materials are commonly described as "industrial vitamins" since they are mainly employed as structural or electronic modifiers rather than as direct catalytic centers. This is because their highly shielded 4f electrons prevent them from effectively participating in interfacial charge transfer. In this work, we break this long-standing limitation by engineering atomically dispersed lanthanum (La) on nitrogen-doped carbon (NC), where it is stabilized in a La-N₄ coordination e