Rational Design of Goethite-Sulfide Nanowire Heterojunctions for High Current Density Water Splitting

• Published in: The journal of physical chemistry letters Vol. 14; no. 29; pp. 6709 - 6718
• Main Authors: Qian, Yinyin, Zhou, Binghui, Zhang, Qiang, Yang, Huaming
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.07.2023
• Subjects: Physical Insights into Materials and Molecular Properties
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.3c01321

The preparation of efficient and stable bifunctional electrocatalysts for electrochemical overall water splitting (OWS) to scale up commercial hydrogen production remains a great challenge. Here, we synthesized heterojunction structures consisting of Co9S8/Ni3S2 nanowire arrays and amorphous goethite (FeOOH, α-phase) particles as efficient OWS catalysts using an interface engineering strategy. The interfacial charge inhomogeneity caused by the heterojunction contact leads to the generation of a built-in electric field, which makes the electron-deficient FeOOH and electron-rich Co9S8/Ni3S2 favorable for hydrogen/oxygen evolution reaction, respectively, thus ensuring the excellent activity of FeOOH/Co9S8/Ni3S2 as a bifunctional catalyst. FeOOH/Co9S8/Ni3S2 exhibits impressive catalytic activity for the oxygen evolution reaction, achieving an ultralarge current density of 1000 mA cm–2 needed as low as 265 mV overpotential, and its stability was tested up to 1440 h. Furthermore, an excellent OWS output (1.55 V to generate 10 mA cm–2) is achieved by the bifunctional FeOOH/Co9S8/Ni3S2 catalysts.