Greenhouse-Gas-Driven Room-Temperature Synthesis of Compositionally Complex Nanomaterials via Anion–Cation Arrangement Control

Multielement nanostructures promise unusual properties but are constrained by crystalline frameworks limiting incorporable cations, and prevailing syntheses rely on harsh conditions restricting practicality. Here we introduce a CO₂-enabled, room-temperature route to nanostructures containing up to 30 different metal cations by coengineering cation and anion arrangements in layered-double-hydroxide-derived frameworks. The key principle is anion-cation arrangement control: CO₂-derived carbonate acts as a programmable bridging anion that, with larger-radius and higher-valent cations, drives structural reconstruction, suppresses long-range order, and relaxes radius-ratio constraints. This reorganization yields uniform cation mixing, tunable M³⁺/M²⁺ balance, and direct metal-carbonate linkages, producing ultrahigh configurational and positional disorder. The synthesis proceeds under ambient conditions in carbonated water, enabling compositional tunability, equimolar incorporation across 30 elements, and scalable, ecofriendly processing that valorizes a greenhouse gas. Leveraging anion-cation coarrangement to expand the composition space offers a general strategy for designing multielement nanomaterials with enhanced functional freedom.