High-Entropy Engineering in Hollow Layered Hydroxide Arrays to Boost 5-Hydroxymethylfurfural Electrooxidation by Suppressing Oxygen Evolution

The electricity-driven 5-hydroxymethylfurfural (HMF) oxidation reaction has exhibited increasing potential to produce high-value-added 2,5-furandicarboxylic acid (FDCA). Unfortunately, the competitive oxygen evolution reaction (OER) can decrease the yield and Faradaic efficiency (FE) of FDCA under high potentials. Here, we report a general MOF-templated strategy to construct a new class of hollow high-entropy layered hydroxide array (HE-LHA) electrocatalysts including quinary, senary, and septenary phases composed of CoNiMnCuZn with Cd and Mg on carbon cloth (CC) for boosting the HMF oxidation reaction (HMFOR) by suppressing the OER. Impressively, the septenary CC@CoNiMnCuZnCdMg-LHA exhibits a low potential of 1.42 V_RHE for the HMFOR but a high potential of 1.68 V_RHE for the OER to achieve 100 mA cm^-2, ranking it among one of the best electrocatalysts for the HMFOR. Finite element simulations show its hollow array morphology can induce a strong local electric field over all of the shell, thus favoring the electrocatalytic process. In situ electrochemical impedance spectroscopy and theoretical calculations further reveal that the Co, Ni, Cu, Zn, Mn, Cd, and Mg metals in high-entropy LHAs can accelerate the HMFOR but suppress the OER by optimizing the adsorption energy of the HMF* and OH*. This work sheds light on the rational design and construction of high-entropy nanoarchitectures for advanced electrocatalysis.