Cu-Metal Organic Framework Derived Multilevel Hierarchy (Cu/Cu x O@NC) as a Bifunctional Electrode for High-Performance Supercapacitors and Oxygen Evolution Reaction

A Cu-metal organic framework (MOF) wasdesigned and synthesizedand further utilized as a precursor source for MOF-derived multilevelhierarchy (Cu/Cu x O@NC) and, further, studiedfor supercapacitors (both two- and three-electrode systems) and OERactivity. Thedevelopment of a MOFs-derived multilevel hierarchyin a singlestep still remains a challenging task. Herein, we have synthesizednovel Cu-MOF via a slow diffusion method at ambient temperature andfurther utilized it as a precursor source for MOF-derived multilevelhierarchy (Cu/Cu x O@NC, x = 1 and 2). This studies suggest that the organic ligands servedas a source of an N-doped carbon matrix encapsulated with metal oxidenanoparticles which were confirmed by various characterization techniques;further BET analysis reveals a surface area of 178.46 m(2)/g. The synthesized multilevel hierarchy was utilized as an electro-activematerial in a supercapacitor that achieved a specific capacitanceof 546.6 F g(-1) at a current density of 1 A g(-1) with a higher cyclic retention of 91.81% after 10 000GCD cycles. Furthermore, the ASC device was fabricated using Cu/Cu x O@NC as the positive electrode and carbonblack as the negative electrode and utilized to enlighten the commerciallyavailable LED bulb. The fabricated ASC device was further employedfor a two-electrode study which achieved a specific capacitance of68 F g(-1) along with a comparable energy densityof 13.6 Wh kg(-1). Furthermore, the electrode materialwas also explored for the oxygen evolution reaction (OER) in an alkalinemedium with a low overpotential of 170 mV along with a Tafel slopeof 95 mV dec(-1) having long-term stability. The MOF-derivedmaterial has high durability, chemical stability, and efficient electrochemicalperformance. This work provides some new thoughts for the design andpreparation of a multilevel hierarchy (Cu/Cu x O@NC) via a single precursor source in a single step and exploredmultifunctional applications in energy storage and an energy conversionsystem.