Phosphoryl-Engineered MOFs Promote Interfacial Reconstruction for Efficient Seawater Ethanol Electrooxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient hydrogen production via seawater electrolysis requires catalysts with high activity and chlorine corrosion resistance in alkaline conditions.
• Developing protective layers on catalysts that simultaneously improve corrosion resistance and anodic reaction activity is a significant challenge.

Purpose of the Study:

• To engineer metal-organic frameworks (MOFs) into catalytic materials with enhanced alkaline seawater ethanol oxidation reaction (EOR) activity and chlorine (Cl-) corrosion resistance.
• To establish a structure-performance correlation between MOF evolution and catalytic properties for hybrid seawater electrolysis.

Main Methods:

• Synthesized a phosphorus-containing MOF (Pa-Ni-TPA) by substituting terephthalic acid (TPA) with 4-phosphonobenzoic acid (Pa).
• Investigated the in situ transformation of MOFs into metal oxyhydroxides containing oxygen anions under alkaline seawater EOR conditions.
• Analyzed the role of incorporated phosphate (PO4 3-) in enhancing EOR activity and Cl- corrosion resistance.

Main Results:

• The Pa-Ni-TPA derived metal oxyhydroxide incorporated PO4 3-, unlike conventional Ni-TPA derived materials.
• PO4 3- facilitated ethanol adsorption and inhibited Cl- adsorption on nickel centers, boosting EOR activity.
• The modified catalyst exhibited significantly enhanced activity and superior resistance to chlorine corrosion.

Conclusions:

• Phosphonyl-ligand engineering of MOFs provides a versatile strategy for creating robust catalytic materials for alkaline seawater electrolysis.
• In situ formation of PO4 3--containing layers effectively protects catalysts against chlorine corrosion while enhancing EOR performance.
• The study demonstrates a clear link between MOF structural modification, catalytic performance, and corrosion resistance.