Derived-2D Nb4C3Tx sheets with interfacial self-assembled Fe-N-C single-atom catalyst for electrocatalysis in water splitting and durable zinc-air battery

In pursuit of advanced nanocatalysts with multifunctionality, cost-effectiveness and durability for water splitting and zinc-air batteries, we unveil a novel strategy by combination of electrochemically etched Nb4C3Tx-MXene nanosheets with Fe-N-C single-atom catalyst. The resultant Fe-N-C/Nb4C3Tx demonstrates exceptional electrocatalytic performances for the ORR (E1/2 = 0.911 V), OER (η10 = 1.52 V), and HER (η10 = 91 mV) in the alkaline media. Besides, the catalyst shows excellent application in water splitting electrolyzer, only requiring 1.58 V for a current density of 10 mA cm−2. Further, the Fe-N-C/Nb4C3Tx assembled battery displays an open-circuit voltage of 1.51 V, a higher peak power density (136 mW cm−2), a narrower polarization gap (0.85 V), and remarkable stability (660 cycles over 220 h), surpassing the Pt/C + RuO2 based counterpart. Our study integrates DFT calculations to guide the catalyst design, laying the foundation for development of reliable and effective trifunctional catalysts in advanced energy-related systems.