Integrating Interactive Noble Metal Single-Atom Catalysts into Transition Metal Oxide Lattices.

Noble metals have broad prospects for catalytic applications yet are restricted to a few packing modes with limited structural flexibility. Here, we achieved geometric structure diversification of noble metals by integrating spatially correlated noble metal single atoms (e.g., Pt, Pd, and Ru) into the lattice of transition metal oxides (TMOs, e.g., Co 3 O 4 , Mn 5 O 8 , NiO, Fe 2 O 3 ). The obtained noble metal single atoms exhibited distinct topologies (e.g., crs , fcu-hex-pcu , fcu , and bcu-x ) from those of conventional metallic phases. For example, Pt single atoms with a crs topology (Pt crs -Co 3 O 4 ) are endowed with synergy of metal-metal and metal-support interactions. A quantitative relationship between various Pt topologies determined by TMO substrates and their electrocatalytic activities was established. We anticipate that this type of interactive single-atom catalysts can bridge the geometric, topological, and electronic structure gaps between the "close-packed" nanoparticles and isolated single atoms as two common categories of heterogeneous catalysts.