Synthesis and catalytic activity of Ag nanoparticles dispersed on nitrogen-doped GOPx toward direct electrooxidation of formaldehyde

Abstract

Silver nanoparticles (Ag NPs) were synthesized and dispersed on the electronically conductive and electrochemically accessible surface of a GOPx composite, which was then employed as a probe for formaldehyde (HCHO) oxidation. The surface nanostructure, crystallographic properties, and oxidation state of the metal present in the GOPx-Ag nanocomposite were investigated using high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. HCHO electrooxidation was evidenced by the appearance of a very well defined anodic peak with an onset potential of −0.783V, which is unique in the literature. The effect of various electroanalytical parameters like concentration, scan rate, and upper potential limit was investigated toward HCHO electrooxidation on GOPx-Ag catalyst. Amperometric study showed remarkable HCHO electrooxidation response with a wide linear range of 1μM–70mM, limit of detection (LOD) 0.167μM, limit of quantification (LOQ) 0.556μM and sensitivity of 35.74μAmM−1cm−2. The experimental results further indicated the long-term stability and practical feasibility of the GOPx-Ag catalyst, with excellent recoveries for HCHO oxidation. The remarkable catalytic efficiency and anti-poisoning properties were far superior to those of many previously reported HCHO sensors. The astonishing analytical performance of GOPx-Ag opens up a new path for fabricating promising HCHO sensors.