Silver nanoparticles-loaded copper (II)-terephthalate framework nanocomposite as a screen-printed carbon electrode modifier for amperometric nitrate detection

Abstract

• Ag NPs/Cu-BDC MOF hybrid was synthesized and applied as a modifier of screen-printed carbon electrode. • The synergetic electrocatalytic effect of Ag NPs/Cu-BDC MOF hybrid resulted in excellent nitrate detection capability. • The possible mechanism of electrochemical nitrate detection on the developed sensor is explained. • The practical utility of the proposed sensor for quantifying nitrates in environmental samples has been demonstrated. Nitrate, the predominant and beneficial form of nitrogen in the environment, has been classified as an inorganic pollutant due to its negative impact on ecosystems and human health when overexposed. Herein, we investigate a hybrid of silver nanoparticles (Ag NPs) and copper (II)-terephthalate metal–organic frameworks (Cu-BDC MOFs) as modifiers of screen-printed carbon electrodes (SPCEs) for electrocatalytic detection of nitrate. In-situ deposition of Ag NPs on surfaces of Cu-BDC MOFs synthesized using a solvothermal approach yielded Ag NPs/Cu-BDC MOF hybrids. Cuboid-shaped Cu-BDC MOFs made it possible to attach many spherical-shaped Ag NPs to them, boosting the electrical conductivity of the hybrid and nitrate reduction efficiency. The sensor performed well in optimal amperometric conditions (-0.80 V vs. Ag/AgCl) with an excellent sensitivity of 1159.8 μA mM −1 cm −2 and a detection limit of 0.24 µM (S/N = 3) in an extended linear range of 0.5 to 1000 µM. Additionally, the sensor demonstrated excellent reproducibility, repeatability, stability, and anti-interference capabilities. More importantly, the sensor was used to assess nitrate in water and soil extracts with recoveries ranging from 97.8 to 102%, effectively detecting nitrate and suggesting potential applicability in environmental samples.