Layered double hydroxide-based single-atom catalysts: precise catalyst design on a two-dimensional ‘atomic canvas’

Layered double hydroxides (LDHs), with their atomically tunable layer composition, abundant surface coordination sites, and modifiable two-dimensional confined interlayer space, offer an ideal ‘atomic canvas’ for the precise design and in situ modulation of single-atom catalysts. The review elaborates on this core concept, systematically presenting synthesis strategies for the precise construction of single-atom sites on LDHs, including in situ growth, post-synthetic anchoring, and topological transformation pathways. Furthermore, the article focuses on leveraging the dynamic properties and synergistic effects of the LDH supports. Multi-dimensional strategies, such as electronic modulation, coordination engineering, interfacial synergy, and reaction pathway reconstruction, are discussed for the rational enhancement of catalytic performance and functional expansion. Despite rapid progress, challenges remain, including the stability of single atoms under high loading, elucidation of dynamic catalytic mechanisms, and scalable fabrication. Future research should integrate advanced characterization and theoretical calculations to clarify the dynamic interactions between the ‘canvas’ and single atoms, and promote the practical application of these high-performance catalysts in energy conversion and green synthesis.