Synergistic coupling effect and anionic modulation of CoFeLDH@MXene for triggered and sustained alkaline water/seawater electrolysis.

Abstract

The application of seawater splitting is crucial for hydrogen production; therefore, efficient electrocatalysts are necessary to prevent chlorine evolution and severe corrosion. A synergistic method is employed on CoFe LDH by integrating a conductive Ti3C2Tx MXene layer and subsequently applying anionic modulation. Robust metal-substrate interaction along with subsequent phosphidation facilitates efficient electron transfer and optimises the electronic structure of Co and Fe sites. The CoFe-P-1000@Ti3C2Tx/CC demonstrates commendable electrochemical performance, requiring overpotentials of 106.6 mV and 276 mV for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at 10 mA cm-2 in 1M KOH electrolyte, while 292 mV is necessary for OER in a simulated seawater electrolyte (1 M KOH + 0.5 M NaCl). Furthermore, the CoFe-P-1000@Ti3C2Tx/CC exhibits an encouraging cell voltage of 1.59 V (j = 10 mA cm-2) for comprehensive alkaline seawater splitting, maintaining exceptional stability for over 50 hours.