Published on July 2019 | Material Science

Zinc-Doped Mesoporous Graphitic Carbon Nitride for Colorimetric Detection of Hydrogen Peroxide

Recently, graphitic carbon nitride (g-C3N4) has been explored as a peroxidase-like catalyst for the nonenzymatic colorimetric detection of H2O2. In this study, we have developed a simple, low cost, and eco-friendly hydrogen bond assisted soft template method of zinc ions doping in mesoporous graphitic-carbon-nitride (Zn-mpg-C3N4) thin nanosheets. Morphology and composition of prepared samples were determined by different characterization techniques. PEG-1500 was beneficial to enhance the porosity and surface area of g-C3N4, whereas zinc loading in the framework of g-C3N4 resulted in the increase in electrical properties. The peroxidase-like catalytic activity of samples was investigated and compared based on the development of blue reaction mixture by the oxidation reaction between 3,3′,5,5′-tetramethylbenzidine and hydrogen peroxide (H2O2) through the colorimetric method. The as-prepared 10% Zn-mpg-C3N4 has shown higher peroxidase-like activity as compared to natural HRP, g-C3N4, and mpg-C3N4. This enhanced peroxidase-like activity was attributed to the thin structured nanosheets, higher specific surface area, outstanding electron transfer ability, increased band gap, and increased in charge separation of the catalyst through the direct zinc ions doping modification. The steady-state kinetics mechanism was investigated by using Michaelis–Menten kinetics, and it was found that the reaction followed a ping-pong mechanism. This outstanding catalytic activity permitted us to design a rapid and convenient colorimetric sensing method to detect H2O2. Under the optimized condition, the developed sensor exhibited a linear range of 10–2000 μM (R2 = 0.9981), limit of detection of 1.4 μM, and limit of quantification of 3.0 μM for H2O2 detection. In view of advantages compared with previous methods such as simple, facile operation, cost-effectiveness, eco-friendliness, naked eye observation, and rapid response, the developed sensor possesses huge potential and is a promising candidate for enzyme mimic sensing of H2O2 in environmental and biological samples.