Sea urchin-like sulfur-doped Ni(OH)₂ as an efficient electrocatalyst for oxygen evolution reaction

The development of high-performance and cost-effective electrocatalysts toward the oxygen evolution reaction (OER) is remarkably desirable but challenging. Herein, we design and fabricate a sea urchin-like S-doped Ni(OH)₂ electrocatalyst on nickel foam using a simple hydrothermal method, followed by treatment with Na₂S solution. The introduction of S not only modulates the electronic structure of Ni(OH)₂, but also improves the electronic conductivity, thus enhancing the OER performance of Ni(OH)₂. Owing to the free-standing feature, modified electronic structure, and sea urchin-like structure, the optimized S-Ni(OH)₂–30 min delivers excellent OER performance with overpotentials of 306 and 392 mV at 10 and 100 mA cm⁻², respectively, Tafel slope of 89.2 mV dec⁻¹, and stability for 30 h at 50 mA cm⁻². This work demonstrates the importance of incorporating S in Ni(OH)₂ to optimize the electronic structure for improving OER activity and provides a promising pathway to synthesize Ni(OH)₂-based electrocatalysts.