MOF-derived chalcogenides multifunctional heterostructure materials for high-performance supercapacitor and oxygen evolution reaction catalytic activity

Abstract

Conventional electrode materials are generally optimized for a specific function, and therefore often possess one or more of the following: low electrical conductivity, less active site utilization, sluggish ion-electron kinetics, and poor structural stability, thus limiting their multifunctional viability. Therefore, we report the synthesis of a series of ZIF-12-derived, post-synthesis metal-modified composite heterostructures: Cu/Zn/Co@NPC, Cu₂Se/ZnSe/CoSe₂@NPC, and Cu₂S/ZnS/CoS₂@NPC achieved through direct thermal treatment of the MOF under an inert atmosphere. The synthesized composites are comprehensively investigated for supercapacitor and oxygen evolution reaction applications. Among all the fabricated composites, Cu₂S/ZnS/CoS₂@NPC demonstrates the highest specific capacitance of 1206 F g⁻¹ at 1 A g⁻¹, outperforming both the Cu/Zn/Co@NPC (620 F g⁻¹) and Cu₂Se/ZnSe/CoSe₂@NPC (894 F g⁻¹). The low charge transfer resistance of 0.175 Ω for Cu₂S/ZnS/CoS₂@NPC is indicative of enhanced electrical conductivity and facile charge transport. An asymmetric supercapacitor device assembled using Cu₂S/ZnS/CoS₂@NPC achieves a specific capacitance of 114 F g⁻¹ at 3 A g⁻¹ and delivered an energy density of 15.83 Wh kg⁻¹ at a power density of 1.5 kW kg⁻¹ with capacity retention of 92.1% over 6000 cycles. Additionally, Cu/Zn/Co@NPC, Cu₂Se/ZnSe/CoSe₂@NPC, and Cu₂S/ZnS/CoS₂@NPC exhibit overpotentials of 150, 140, and 120 mV at 10 mA cm⁻² whose Tafel slopes are 180, 103, and 92 mV dec⁻¹, respectively. The bifunctional Cu₂S/ZnS/CoS₂@NPC composite demonstrates superior performance which can be assigned to its enhanced electrical conductivity, abundant redox active sites, superior heterointerfaces, and robust architecture all of which facilitate rapid charge transfer. This work demonstrates the potential of MOF-derived multimetal chalcogenide heterostructures embedded in nitrogen doped porous carbon to act as efficient and multifunctional electrode materials for energy storage and conversion technologies.