Ni/NiO nanosheets for alkaline hydrogen evolution reaction: In situ electrochemical-Raman study. (20th November 2020)

• Record Type: Journal Article
• Authors: Faid, Alaa Y.; Barnett, Alejandro Oyarce; Seland, Frode; Sunde, Svein
• Is Part Of: Electrochimica acta. Volume 361(2020)
• Publication Date: 2020-11-20
• Subjects: Ni/NiO -- Hydrogen evolution -- In situ raman -- Alkaline electrolysis; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.137040
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Ni/NiO catalyst exhibits superior HER activity compared to Ni or NiO bare. In situ raman shows that Ni/NiO maintains Ni(OH)2 species initially during HER. Ni/NiO lose Ni(OH)2 species by preserving −0.4 V vs. RHE for 2000 sec. Abstract: Nickel/Nickel oxide (Ni/NiO) nanosheets heterostructure is a cheap and active catalyst for hydrogen evolution reaction (HER) in alkaline electrolytes. However, the reason for this activity is still under debate. Herein in-situ Raman electrochemistry has been established as a method to probe interfacial intermediates and correlate the performance of various nickel catalysts (Ni, NiO, and Ni/NiO nanosheets) during HER. In-situ Raman spectroscopy demonstrated that Ni/NiO nanosheet heterostructure maintained β-Ni(OH)2 species initially, which may contribute to the superior initial HER activity. Ni/NiO nanosheets lost β-Ni(OH)2 species by preserving a high cathodic overpotential (-0.4 V vs. RHE) for 2000 sec. The results confirmed the importance of Ni metal sites in addition to NiO sites and maintaining hydroxide species for superior and durable HER activity. These results can be utilized to design an efficient and durable catalyst for alkaline electrolyzers for the sustainable production of hydrogen. Graphical abstract: Image, graphical abstract