Transitioning from hydroxides to sulfides: Enhancing the catalytic activity of NiAl-layered double hydroxide for improved water oxidation efficiency

Currently, NiAl-LDH-based catalysts have been developed using a simple one-step method with Na ₂ S as the sulfur source for the sulfidation process, which exhibit high performance for water oxidation in alkaline media. In this work, the NiAl-layered double hydroxide (NiAl-LDH-S-50%) was synthesized via a hydrothermal method followed by the sulfidation treatment, in which there was a promoted efficient electron transfer. Furthermore, the effect of S/(Ni and Al) ratio on catalytic performance of the samples was examined. It was found that the NiAl-LDH-S-50% sample demonstrated an outstanding water oxidation activity, and required only overpotentials of about 100 and 190 mV to reach the current densities of 10 and 50 mA cm ⁻² , respectively. Such a good performance of NiAl-LDH-S-50% was attributed to low charge transfer resistance (5.2 Ω cm ^− 2 ) due to its excellent electrical conductivity. Moreover, the as-prepared electrocatalyst showed remarkable stability and durability after 24 h of continuous water oxidation. This study presents a promising approach to improve water oxidation performance by optimizing the electronic structure of the NiAl-LDH-S sample with low Tafel slope about 67 mV.dec ^− 1 .