Supplementary Materials

Computational methods; Possible sites for single atom supported on substrates; The Eb of Th atom supported on different sites and a single M atom supported on substrates; Diffusing energy barriers and FPMD of U atom on the GDY; The PDOS and CDD of Th@sub and U@sub; Adsorption energies (Eads), and distances (dN≡N); The ∆G profiles of Th@sub; The M−N bond distances; Schematics of electron donation-backdonation mechanism; The PDOS of the Ce@GN4; Structures, Bader charges, and CDD graph of three moieties for the NxHy adsorbed on U@GN4.