High-Entropy Engineering in Hollow Layered Hydroxide Arrays to Boost 5-Hydroxymethylfurfural Electrooxidation by...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a promising route for producing valuable chemicals.
• The oxygen evolution reaction (OER) often competes with HMF oxidation, reducing yield and Faradaic efficiency (FE).

Purpose of the Study:

• To design and synthesize novel electrocatalysts for efficient HMF oxidation.
• To suppress the competing oxygen evolution reaction (OER) during HMF electrooxidation.
• To investigate the structure-activity relationship of high-entropy layered hydroxide arrays (HE-LHAs) in HMF oxidation.

Main Methods:

• MOF-templated synthesis of hollow high-entropy layered hydroxide array (HE-LHA) electrocatalysts.
• Electrochemical characterization including cyclic voltammetry and chronoamperometry.
• Finite element simulations and *in situ* electrochemical impedance spectroscopy (EIS).
• Density functional theory (DFT) calculations.

Main Results:

• A series of quinary, senary, and septenary HE-LHAs composed of Co, Ni, Mn, Cu, Zn, Cd, and Mg were successfully synthesized on carbon cloth.
• The septenary HE-LHA (CC@CoNiMnCuZnCdMg-LHA) demonstrated superior performance for HMF oxidation, achieving 100 mA cm^-2 at a low potential of 1.42 V_RHE.
• The HE-LHA structure effectively suppressed the OER, with a potential of 1.68 V_RHE required for OER to reach the same current density.
• Finite element simulations revealed that the hollow array morphology induces a strong local electric field, enhancing catalysis.
• *In situ* EIS and DFT calculations indicated that the high-entropy composition optimizes HMF* and OH* adsorption, favoring HMF oxidation and suppressing OER.

Conclusions:

• MOF-templated synthesis provides a general strategy for constructing hollow HE-LHAs for electrocatalysis.
• The developed HE-LHAs are highly effective electrocatalysts for HMF oxidation to FDCA, showing excellent selectivity and efficiency.
• The rational design of high-entropy nanoarchitectures offers a promising pathway for advancing electrocatalytic applications.