DFT Investigation on Transition-Metal Cr-, Mo-, and W-Doped MXene Nb2CO2 Nanosheets: Implications for High-Performance H2, CO, and H2S Gas Sensors

As a clean and sustainable energy storage technology, zinc-air batteries (ZABs) offer significant potential for future applications. However, the development of efficient, stable, and cost-effective non-precious metal catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is essential for the widespread adoption of ZABs. In this study, Fe-NX is anchored onto nitrogen and oxygen co-doped carbon nanofibers (N,O-CNF) through a straightforward electrospinning technique, with the N and O species content further optimized via HCl etching and NH3 activation to enhance catalytic performance. In a 0.1 M KOH solution, the resulting Fe-NX@N,O-CNF-act catalyst displays superior ORR activity compared to Pt/C and OER performance comparable to that of RuO2. Additionally, it demonstrates excellent methanol tolerance and long-term stability. The assembled battery exhibits a peak power density significantly higher than that of Pt/C (113.63 mW cm-2vs. 86.26 mW cm-2), along with improved cycling stability and battery round-trip efficiency (453 cycles, 50.2%) compared to Pt/C + RuO2 (427 cycles, 44.2%). These results highlight its promising potential for applications in energy storage and conversion.