Efficient and sustainable water electrolysis achieved by excess electron reservoir enabling charge replenishment to catalysts

• Published in: Nature communications Vol. 14; no. 1; p. 5402
• Main Authors: Lee, Gyu Rac, Kim, Jun, Hong, Doosun, Kim, Ye Ji, Jang, Hanhwi, Han, Hyeuk Jin, Hwang, Chang-Kyu, Kim, Donghun, Kim, Jin Young, Jung, Yeon Sik
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.09.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/146; 142/126; 147/28; 639/301/299/161/886; 639/301/299/886; 639/301/357; 639/4077/909/4086; 639/925/357; Antimony; Catalysts; Charge transfer; Electrolysis; Electrons; Humanities and Social Sciences; Hydrogen production; multidisciplinary; Nanoparticles; Oxidation; Oxygen; Oxygen evolution reactions; Replenishment; Reservoirs; Science; Science (multidisciplinary); Tin oxide; Tin oxides; Water splitting
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41102-2

Suppressing the oxidation of active-Ir(III) in IrO x catalysts is highly desirable to realize an efficient and durable oxygen evolution reaction in water electrolysis. Although charge replenishment from supports can be effective in preventing the oxidation of IrO x catalysts, most supports have inherently limited charge transfer capability. Here, we demonstrate that an excess electron reservoir, which is a charged oxygen species, incorporated in antimony-doped tin oxide supports can effectively control the Ir oxidation states by boosting the charge donations to IrO x catalysts. Both computational and experimental analyses reveal that the promoted charge transfer driven by excess electron reservoir is the key parameter for stabilizing the active-Ir(III) in IrO x catalysts. When used in a polymer electrolyte membrane water electrolyzer, Ir catalyst on excess electron reservoir incorporated support exhibited 75 times higher mass activity than commercial nanoparticle-based catalysts and outstanding long-term stability for 250 h with a marginal degradation under a water-splitting current of 1 A cm −2 . Moreover, Ir-specific power (74.8 kW g −1 ) indicates its remarkable potential for realizing gigawatt-scale H 2 production for the first time. Charge replenishment from the supports to catalysts can play a key role in stabilizing active-Ir(III) to realize an efficient and durable oxygen evolution reaction. Here, the authors report an excess electron reservoir, greatly enhancing charge donation for improved water-splitting performance.