Effect of Synthetic Methodology on the Physicochemical Attributes and Electrocatalytic Activity of NiAl‐LDHs for the Oxygen Evolution Reaction

• Published in: Chemistry, an Asian journal an Asian journal, 2024-08, Vol.19 (16), p.e202300625-n/a
• Main Authors: Hanif, Aamir, Khan, M. Yusuf, Ehsan, M. Ali, Helal, Aasif, Abdul Aziz, M., Khan, Abuzar
• Format: Article
• Language: English
• Subjects: AMOST; Delaminated LDH; Electrolysis; Exfoliation; Hydrolysis; Hydroxides; Intermetallic compounds; Ni-Al 2D LDH; Nickel aluminides; Nickel base alloys; Nickel compounds; Oxygen evolution reaction (OER); Oxygen evolution reactions; Surface area; Ureas; Water Splitting
• ISSN: 1861-4728; 1861-471X; 1861-471X
• DOI: 10.1002/asia.202300625

Layered double hydroxides (LDHs) are promising materials for oxygen evolution reactions (OERs), a key component of water splitting to produce hydrogen and oxygen via water electrolysis. However, the performance of LDHs can be limited by their low surface area and poor accessibility of active sites. In this work, we synthesized highly exfoliated 2D NiAl‐LDHs by aqueous miscible solvent treatment method (AMOST) and compared its electrocatalytic efficiency with its analogue synthesised via slow urea hydrolysis. We demonstrate that the exfoliated 2D LDHs prepared by AMOST method have a higher surface area and more active sites than the crystalline LDHs obtained through urea hydrolysis, resulting in a superior OER activity and efficiency. The exfoliated 2D LDHs required a lower overpotential of 280 mV to reach a current density of 50 mA cm−2 and it also outperformed IrO2, a benchmark OER catalyst, in terms of overpotential and stability. We demonstrate that the physicochemical properties of nanosheets derived from NIAl‐LDH‐based materials are strongly influenced by the synthetic methodology, which affects the exfoliation degree, surface area and active site density. These factors are crucial for improving the OER catalytic performance of these materials, as shown by our results. Exfoliated NiAl LDH synthesized by aqueous miscible organic solvent treatment exhibited a lower overpotential and higher current density than its analogues due to more accessible active catalytic sites.