Fe nanoparticles confined by multiple-heteroatom-doped carbon frameworks for aqueous Zn-air battery driving CO2 electrolysis

Metal-organic frameworks (MOF) derived carbon materials are considered to be excellent conductive mass transfer substrates, and the large specific surface area provides a favorable platform for loading metal nanoparticles . Tuning the coordination of metals through polyacid doping to change the MOF structure and specific surface area is an advanced strategy for designing catalysts. Modification of Fe-doped ZIF-8 pre-curing by pyrolysis of phosphomolybdic acid hydrate (PMo), Fe nanoparticles confined by Mo and N co-doped carbon frameworks (Fe-NP/MNCF) were fabricated, and the impact of PMo doping on the shape and functionality of the catalysts was investigated. The Zn-air battery (ZAB) driven CO 2 electrolysis was realized by using Fe-NP/MNCF, which was used as bifunctional oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO 2 RR) catalysts. The results show that the half-wave potential (E 1/2 ) of Fe-NP/MNCF is 0.89 V, and the limiting diffused current density ( j L ) is 6.4 mA cm −2 . The ZAB constructed by Fe-NP/MNCF shows a high specific capacity of 794.8 mAh g Zn −1 , a high open-circuit voltage (OCV) of 1.475 V, and a high power density of 111.6 mW cm −2 . Fe-NP/MNCF exhibited efficient CO 2 RR performance with high CO Faraday efficiency (FE CO ) of 87.5 % and current density for the generation of carbon dioxide ( j CO ) of 10 mA cm −2 at −0.9 V vs RHE. ZAB-driven CO 2 RR had strong catalytic stability. These findings provide new methods and techniques for the preparation of advanced carbon-based catalysts from MOFs.