Coordinatively Unsaturated Metal-Nitrogen Active Sites at Twisted Surfaces in Metallic Porous Nitride Single Crystals...

To create active sites on surfaces, the identification of structural features that could confine the local-defect structure in the lattice is required. Porous nitride single crystals, combining the advantages of porosity and structural coherence, provide the possibility to create coordinatively unsaturated metal-nitrogen active sites confined on surfaces. For the first time, ordered active sites and tailor the atomically resolved Fe-N and Co-N local structures are created through control of the unsaturated nitrogen coordination at twisted surfaces in porous single-crystalline Fe_n N (n=2-4) and Co_n N (n=1-3) nanocubes. The precise tailoring of the electronic structures of these coordinatively unsaturated active sites therefore engineer the catalytic activity. Optimum electrocatalysis performances are observed with the porous Fe₄ N and Co₃ N nanocubes with highly unsaturated nitrogen coordination for selective nitrate reduction to ammonia and nitrobenzene amination to aminobenzene, while the structural coherence of these porous nitride single crystals delivers excellent durability.