Alpha‐Nickel Hydroxide Coating of Metallic Nickel for Enhanced Alkaline Hydrogen Evolution. Issue 18 (9th August 2022)

• Record Type: Journal Article
• Authors: Xue, Song; Liang, Yunchang; Hou, Shujin; Zhang, Yajing; Jiang, Heqing
• Is Part Of: ChemSusChem. Volume 15:Issue 18(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-09
• Subjects: electrolysis -- hydrogen evolution -- nickel -- synergy -- water splitting; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.202201072
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: In this work, alkaline hydrogen evolution reaction (HER) processes of three typical nickel‐based electrocatalysts [i. e., Ni, α‐Ni(OH)2, and β‐Ni(OH)2 ] were investigated to probe critical factors that determine the activity and durability. The HER activity trend was observed as Ni≫α‐Ni(OH)2 >β‐Ni(OH)2, likely attributed to a synergy between metallic Ni and Ni(OH)2 components on the Ni surface and fast water dissociation kinetics on the α‐Ni(OH)2 surface. With the HER proceeding, the metallic Ni surface, however, gradually became α‐Ni(OH)2, and α‐Ni(OH)2 surface ultimately transformed into β‐phase, leading to a dramatic activity decrease of Ni electrodes. Therefore, Ni electrodes were coated with α‐Ni(OH)2 nanosheets to slow down the nickel hydroxylation and optimize the surface ratio of Ni(OH)2 to metallic Ni. This simple coating procedure enhanced both activity and durability of Ni electrocatalysts. Abstract : Alpha type : The alkaline hydrogen evolution reaction activity of typical nickel‐based catalysts follows the trend of Ni≫α‐Ni(OH)2 >β‐Ni(OH)2, but with the reaction proceeding, their activity decreases dramatically due to a hydroxylation and phase transition. Here, Ni electrodes are coated with α‐Ni(OH)2 nanosheets to slow down the Ni hydroxylation and optimise the surface ratio of Ni(OH)2 to Ni. Subsequently, both activity and stability are enhanced.