High-entropy materials based on deep eutectic solvent for boosting oxygen evolution reaction

Abstract

High-entropy materials (HEM) are promising electrocatalysts for oxygen evolution reaction (OER) because of their instinctive physicochemicalproperties and highly tailorable electrochemical properties. However, their synthesis and morphology control remains challenging due to the thermodynamic immiscibility of multimetallic elements under mild conditions. Deep eutectic solvents (DESs) as solvents and temples can affect the morphology and electrochemical performance of OER. Herein, a series of HEM electrocatalysts based on different DESs were synthesized to investigate the effect of DES on the morphology and OER performance of catalysts. The influence of metals on OER performance was further explored. Among them, poly-(ethylene glycol)/thiourea-based HEM catalyst (PEG/TU-NiFeCoMnAl) shows excellent OER performance with an overpotential of only 220 mV and 317 mV at10 mA cm−2 and 100 mA cm−2, respectively. Finally, the influence of different metal active sites on OER performance was analyzed by DFT calculations, and scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma-optical emission spectroscopy (ICP-OES) X-raydiffraction (XRD),X-ray photoelectron spectroscopy (XPS) andtransmission electron microscopes (TEM)characterizationtestingtechnologies. This work provides a new direction for the construction of advanced high-entropy materials under mild conditions for energy conversion and storage.