Pt/NiCo2O4 nanocomposite with extremely low Pt loading as an oxidase-like nanozyme for colorimetric detection of acetaminophen in natural water

Abstract

BackgroundIn the last COVID-19-three years, acetaminophen (AP) consumption has increased significantly, potentially causing water contamination. Due to its ease of use and great performance, colorimetric detection of AP based on Pt-based nanozymes is gaining popularity. A significant difficulty is how to reduce Pt loading content while retaining a high catalytic activity. MethodsControlling the deamination of Co-NH3 complexes, including Ni(OH)2, led to the formation of small NiCo2O4 nanoparticles, which were afterwards decorated with a 0.37wt% Pt loading. Significant findingsWith a low Michaelis-Menten constant of 0.0112 mM, the 3,3′,5,5′-tetramethylbenzidine (TMB) was oxidized with O2 utilizing the Pt(0.37wt%)/NiCo2O4 nanocomposite. The detection settings were tuned for nanozyme and TMB concentrations, pH, temperature, and reaction duration. Utilizing AP's inhibitory impact on the oxidase-like activity at pH = 1, an AP colorimetric sensor was created. It was possible to establish a linear response with a detection limit (LOD) of 2.4 μM and a range of 10 μM–0.25 mM. In natural water, such as spring, lake, and river water, this colorimetric sensor was effectively employed to detect AP with good selectivity over interfering substances.