Metal‐Triazolate‐Framework‐Derived FeN4Cl1 Single‐Atom Catalysts with Hierarchical Porosity for the Oxygen Reduction Reaction

Abstract The construction of single‐atom catalysts (SACs) with high single atom densities, favorable electronic structures and fast mass transfer is highly desired. We have utilized metal‐triazolate (MET) frameworks, a subclass of metal–organic frameworks (MOFs) with high N content, as precursors since they can enhance the density and regulate the electronic structure of single‐atom sites, as well as generate abundant mesopores simultaneously. Fe single atoms dispersed in a hierarchically porous N‐doped carbon matrix with high metal content (2.78 wt %) and a FeN 4 Cl 1 configuration (FeN 4 Cl 1 /NC), as well as mesopores with a pore:volume ratio of 0.92, were obtained via the pyrolysis of a Zn/Fe‐bimetallic MET modified with 4,5‐dichloroimidazole. FeN 4 Cl 1 /NC exhibits excellent oxygen reduction reaction (ORR) activity in both alkaline and acidic electrolytes. Density functional theory calculations confirm that Cl can optimize the adsorption free energy of Fe sites to *OH, thereby promoting the ORR process. The catalyst demonstrates great potential in zinc‐air batteries. This strategy selects, designs, and adjusts MOFs as precursors for high‐performance SACs.