Bifunctional Cu(II)-based 2D coordination polymer and its composite for high-performance photocatalysis and electrochemical energy storage.

Coordination polymers (CPs) have been widely proven as sacrificial electrode materials for energy storage applications because of their high porosity, specific surface area and tunable structural topology. In this work, a new 2D Cu(II)-based CP, formulated as [Cu 2 (btc)(μ-Cl) 2 (H 2 O) 4 ] n (CP-1) (H 3 btc = benzene-1,3,5-tricarboxylic acid), fabrication of copper oxide nanoparticles (CuO NPs) and its composite (CuO@CP-1) were successfully synthesized using solvothermal, precipitation and mechanochemical grinding approaches. Single-crystal X-ray analysis authenticated a two-dimensional (2D) layered network of CP-1. Further, CP-1, CuO NPs and composite were characterized by diffraction (Powder-XRD), spectroscopic (FTIR), microscopic (SEM), and thermal (TGA) techniques. The porosity and surface behavior of CP-1 and the composite were demonstrated using BET analyzer. Topological simplification of CP-1 shows a 3-c connected hcb periodic net. The photocatalytic behavior of CP-1 was examined over methyl red (MR) dye in the presence of sunlight and showed a promising degradation efficiency of 96.80%. The electrochemical energy storage properties of CP-1, CuO NPs and composite were investigated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analysis under aqueous 1 M H 2 SO 4 electrolyte. The electrochemical results show better charge storage performance of CP-1 with a specific capacitance of 602.25 F g -1 at 1 A g -1 current density by maintaining a retention of up to 84.51% after 5000 cycles at 10 A g -1 current density. Comparative electrochemical studies reveal that CP-1 is a promising electrode material for energy storage.