Chemistry of Actinide Centers in Heterogeneous Catalytic Transformations of Small Molecules

The chemistry of actinide molecules and materials has shown remarkable conceptual advancements in the past decade illustrating their unique reactivity profiles, when compared with lanthanides and transition elements, but there are still some challenging questions on the intriguing stability of low valent states and the significant role of 5f orbitals in bonding and reactivity of actinides. The distinctive electronic flexibility of actinide centers makes them potential catalysts for heterogeneous molecular transformations because of the kinetic lability of their coordination states and facile switching among oxidaton states. Actinide-enabled chemical transformations such as the six-electron reduction of dinitrogen into two reactive ammonia molecules or four-electron oxidation of water into oxygen under mild conditions are promising pathways in the quest of high efficiency heterogeneous catalysts. This Review provides a comprehensive account on actinide-mediated catalytic transformation of small molecules such as CO, CO2, N-2, O-2, H2O, CH4, HCl, and NH3. The emphasis is placed on the emerging phenomena in actinide-based solid catalysts and controlled synthesis of nanostructured actinide materials as pristine and substrate-grown phases. The mechanistic investigations highlight the influence of the 5f electrons in multielectron transfer reactions and the propensity of actinide centers to achieve higher oxidation states that defines the surface termination in actinide oxides. Finally, the status and perspectives of actinide-containing materials beyond the nuclear fuel applications is discussed, underlining their exciting chemistry and unexplored potential toward alternative catalytic energy production processes.