Improved performances toward electrochemical carbon dioxide and oxygen reductions by iron-doped stannum nanoparticles†

The CO₂ reduction reaction (CO₂RR) and oxygen reduction reaction (ORR) show great promise for expanding the use of renewable energy sources and fostering carbon neutrality. Sn-based catalysts show CO₂RR activity; however, they have been rarely reported in the ORR. Herein, we prepared a nitrogen–carbon structure loaded with Fe-doped Sn nanoparticles (Fe–Sn/NC), which has good ORR and CO₂RR activity. The results reveal that the Fe–Sn/NC catalysts deliver a high FE_CO of 99.0% at a low overpotential of –0.47 V in an H-type cell for over 100 h. Notably, a peak power density of 1.36 mW cm⁻² is achieved in the Zn–CO₂ battery with the Fe–Sn/NC cathode at discharge current densities varying from 2.0 to 4.0 mA cm⁻², and the FE_CO remains above 99.0%. Due to efficient oxygen reduction reaction (ORR) performance and Zn–air battery (ZAB) characteristics, the ZAB-driven CO₂RR has strong catalytic stability. This work proves that Fe–Sn/NC enhances the performance of the CO₂RR and ORR, and the study of Zn-based batteries provides a new research direction for energy conversion.