Investigation of a Single Atom Iron Catalyst for the Electrocatalytic Reduction of Nitric Oxide to Hydroxylamine: A DFT Study

Hydroxylamine, as an important reducing agent, disinfectant, foaming agent, and biocide, plays a role in both human life and industrial production. However, its synthesis is confronted with challenges, such as high pollution and large consumption. Here, we propose a coordination tailoring strategy to design 47 graphene-supported single iron atom catalysts (SACs), namely, Fe@C_xZ_y (Z = B, N, O, P, and S), for the reduction of nitric oxide to hydroxylamine. Using density functional theory calculations, we demonstrated the great impact of the coordination environment on the stability, catalytic selectivity, and activity of the Fe site. We identified that the experimentally available Fe@N₄ possesses an ultralow theoretical limiting potential of −0.32 V compared to that of other catalysts. A comprehensive investigation of the electronic properties elucidates the underlying active origin and reaction mechanism of the nitric oxide reduction reaction to hydroxylamine on Fe@N₄. These results not only explain the catalytic origin of synthesized SACs for the NH₂OH production but also offer theoretical guidance for further optimizing high-performance catalysts.