Enhanced the Overall Water Splitting Performance of Quaternary NiFeCrCo LDH: Via Increasing Entropy

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-performance catalysts are essential for overall water splitting (OWS).
• Nickel-iron layered double hydroxides (NiFe LDH) show promise for OWS but suffer from slow hydrogen evolution reaction (HER) kinetics in alkaline media.
• Optimizing catalyst performance is critical for efficient OWS applications.

Purpose of the Study:

• To enhance the overall water splitting (OWS) performance of NiFe LDH catalysts.
• To investigate the effect of entropy engineering on multi-metallic layered double hydroxides (LDH).
• To develop a stable and efficient catalyst for OWS under alkaline and simulated seawater conditions.

Main Methods:

• Construction of quaternary NiFeCrCo LDH by adjusting entropy.
• Electrochemical characterization of OWS, oxygen evolution reaction (OER), and HER.
• Stability testing of the catalyst for OER and HER.
• Evaluation of catalyst performance under simulated seawater conditions.

Main Results:

• Quaternary NiFeCrCo LDH exhibited remarkable OWS activity.
• The OER and HER stability of NiFeCrCo LDH were 100 h and 80 h, respectively.
• NiFeCrCo LDH//NiFeCrCo LDH achieved 10 mA cm^-2 at 1.42 V and 100 mA cm^-2 at 1.54 V.
• Under simulated seawater, the catalyst required 1.57 V for 10 mA cm^-2 and 1.71 V for 100 mA cm^-2.
• Cobalt introduction regulated the electronic state of the catalyst, enhancing performance.

Conclusions:

• Entropy-increase engineering is a viable strategy for developing high-performance OWS catalysts.
• NiFeCrCo LDH demonstrates excellent OWS activity and stability, suitable for alkaline and seawater electrolysis.
• Optimized electronic states in multi-metallic LDHs are key to achieving superior OWS performance.