Cationic Oxidative Leaching Engineering Modulated <i>In Situ</i> Self-Reconstruction of Nickel Sulfide for Superior Water Oxidation
Xuanzhi Liu, Jianchuan Wang, Hanxiao Liao, Jiaoyang Chen, Shaohui Zhang, Liming Tan, Xusheng Zheng, Dewei Chu, Penfei Tan, Jun Pan
Abstract
Tuning the electroactive surface species of electrocatalysts remains a significant challenge for achieving highly efficient oxygen evolution reactions. Herein, we propose an innovative in situ leaching strategy, modulated by cationic oxidation, to achieve active self-reconstruction of these catalysts. Vanadium is introduced as a cation into Ni 3 S 2 and oxidized under low oxidative potential, leading to subsequent leaching into the electrolyte and triggering self-reconstruction. The structural evolution from V-Ni 3 S 2 to Ni(OH) 2 and subsequently to NiOOH is identified by operando Raman as a three-step transition. In contrast, V-free Ni 3 S 2 is unable to bypass the thermodynamically predicted nickel oxysulfide products to transform into active NiOOH. As a result, the self-restructured V-Ni 3 S 2 only needs an ultralow overpotential of 155 mV at 10 mA cm –2, outperforming V-free Ni 3 S 2 and many other advanced catalysts. This work provides new guidelines for manipulating in situ leaching to modulate the self-reconstruction of catalysts.