Multiscale structural engineering of atomically dispersed FeN4 electrocatalyst for proton exchange membrane fuel cells

We report a three-dimensional (3D) metal–organic frameworks (MOF)-derived Fe–N–C single-atom catalyst for proton exchange membrane fuel cells. The multiscale structure engineering from micro- through nano- to atomic scale increases the active Fe-N4 site density and enhances the mass transport in the Fe–N–C catalyst.