Carbon-supported high-entropy Co-Zn-Cd-Cu-Mn sulfide nanoarrays promise high-performance overall water splitting

Transition metal sulfides with homogeneous multi-metallic elements promise high catalytic performance for water electrolysis owing to the unique structure and highly tailorable electrochemical property. Most existing synthetic routes require high temperature to ensure the uniform mixing of various elements, making the synthesis highly challenging. Here, for the first-time novel carbon fiber supported high-entropy Co-Zn-Cd-Cu-Mn sulfide (CoZnCdCuMnS@CF) nanoarrays are fabricated by the mild cation exchange strategy. Benefiting from the synergistic effect among multiple metals and the strong interfacial bonding between high-entropy Co-Zn-Cd-Cu-Mn sulfide nanoarrays and the carbon fiber support, CoZnCdCuMnS@CF exhibits superior catalytic activity and stability toward overall water splitting in alkaline medium. Impressively, CoZnCdCuMnS@CF only needs low overpotentials of 173 and 220 mV to reach the current density of 10 mA·cm−2, with excellent durability for over 70 and 113 h for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) respectively. More importantly, the bifunctional electrode (CoZnCdCuMnS@CF∥CoZnCdCuMnS@CF) for overall water splitting can deliver a small cell voltage of 1.63 V to afford 10 mA·cm−2 and exhibit outstanding stability of negligible decay after 73 h continuous operation. This work provides a viable synthesis route toward advanced high-entropy materials with great potential applications.