A Cost-Effective, Nanoporous, High-Entropy Oxide Electrode for Electrocatalytic Water Splitting

• Published in: Coatings (Basel) Vol. 13; no. 8; p. 1461
• Main Authors: Liu, Bu-Jine, Yin, Tai-Hsin, Lin, Yu-Wei, Chang, Chun-Wei, Yu, Hsin-Chieh, Lim, Yongtaek, Lee, Hyesung, Choi, Changsik, Tsai, Ming-Kang, Choi, YongMan
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2023
• Subjects: Alternative energy sources; Carbon; Charge transfer; Chromium; Copper; Copper oxide; Copper oxides; Cuprite; Electrochemical impedance spectroscopy; Electrode materials; Electrodes; Energy resources; Entropy; Fossil fuels; Green hydrogen; Hydrogen; Oxygen evolution reactions; Radiation; Renewable resources; Scanning electron microscopy; Voltammetry; Water splitting; Taiwan; United States > US
• ISSN: 2079-6412; 2079-6412
• DOI: 10.3390/coatings13081461

High-entropy materials have attracted extensive attention as emerging electrode materials in various energy applications due to their flexible tunability, unusual outstanding activities, and cost-effectiveness using multiple earth-abundant elements. We introduce a novel high-entropy composite oxide with the five elements of Cu, Ni, Co, Fe, and Cr (HEO-3CNF) for use in the oxygen evolution reaction (OER) in electrocatalytic water splitting. HEO-3CNF is composed of two phases with a non-equimolar, deficient high-entropy spinel oxide of (Cu0.2−xNi0.2Co0.2Fe0.2Cr0.2)3O4 and monoclinic copper oxide (CuO). Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times (DRT) analysis validates that the HEO-3CNF-based electrode exhibits faster charge transfer than benchmark CuO. It results in improved OER performance with a lower overpotential at 10 mA/cm2 and a Tafel slope than CuO (518.1 mV and 119.7 mV/dec versus 615.9 mV and 131.7 mV/dec, respectively) in alkaline conditions. This work may provide a general strategy for preparing novel, cost-effective, high-entropy electrodes for water splitting.