Bifunctional Sr(II)-Based Coordination Polymer for Sensing of Ba(II)/Nitro-aromatic Compounds and Supercapacitor Applications

Abstract

Main group element-based coordination polymers (CPs) are being widely studied for energy storage and sensing applications because of their structural versatility and electropositive properties. In this work, Sr(II)-CP namely, (SA2) was fabricated utilizing 3,5-pyridine dicarboxylic acid (PDC). SA2 was confirmed by Single-crystal X-ray diffraction (SC-XRD). The topological rod net representation showed that SA2 followed (6,3) lla underlying net. However, to enhance the electrochemical properties of SA2, a rGO@SA2 composite was fabricated by inducing reduced graphene oxide (rGO) using a sonication approach. SA2, rGO and rGO@SA2 were confirmed by spectroscopic and microscopic techniques (PXRD, FT-IR, TGA, UV-Vis, SEM, and HR-TEM, respectively). SA2 served as an excellent sensor for Ba2+ (92%) metal ions and showed notable fluorescence selectivity for picric acid (PA-95%) among 1,4-nitroaniline (NA-83%) and benzoic acid (BA-49%). Furthermore, the electrochemical analysis was performed using galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) techniques which showed a good specific capacitance of SA2 and rGO@SA2 of 153.57 Fg-1 and 383.38 Fg-1 at a current density of 0.5 A g-1, respectively. After 2000 cycles, rGO@SA2 showed a retention capacitance of 96.32%.