Structural Self-Regulation-Promoted NO Electroreduction on Single Atoms
Xue Yao, Linke Huang, Ethan Halpren, Lixin Chen, Zhiwen Chen, Chandra Veer Singh
Abstract
Simultaneously elevating loading and activity of single atoms (SAs) is desirable for SA-containing catalysts, including single-atom catalysts (SACs). However, the fast self-nucleation of SAs limits the loading, and the activity is confined by the adsorption-energy scaling relationships on monotonous SAs. Here, we theoretically design a novel type of SA-containing catalyst generated by two-step structural self-regulation. In the thermodynamic self-regulation step, divacancies in graphene spontaneously pull up SAs from transition metal supports ( dv -g/TM; TM = fcc Co, hcp Co, Ni, Cu), leading to the expectably high loading of SAs. The subsequent kinetic self-regulation step involving an adsorbate-assisted and reversible vacancy migration dynamically alters coordination environments of SAs, helping circumvent the scaling relationships, and consequently, the as-designed dv -g/Ni can catalyze NO-to-NH 3 conversion at a low limiting potential of −0.25 V vs RHE.