The effect of copper and iron adsorption on the catalytic performance of alumina nanofiber / nanodiamond composite in sensing applications

Ronzhin, N.O., Posokhina, E.D., Mikhlina, E.V., (...), Bondar, V.S., Ryzhkov, I.I.// Journal of Physics and Chemistry of Solids//

Phenolic compounds are common environmental pollutants, which are used in many industries and contaminate water environment due to industrial wastewater discharge. Presently, there is an increasing demand for the development and improvement of inexpensive, easy-to-use analytical tools for in-situ detection of phenolic compounds. In this work, we investigate the effect of adsorption of Cu2+ and Fe2+ ions on the catalytic activity of a composite material based on alumina nanofibers (ANF) and detonation nanodiamonds (DND) in the co-oxidation of phenols with 4-aminoantipyrine in the presence of hydrogen peroxide. We have found more than two-fold increase of the catalytic activity for ANF + DND + Cu composite, while the activity of ANF + DND + Fe composite is found to decrease by several times in comparison with the original ANF + DND material. The results of FTIR analysis indicate that the adsorption of iron ions occurs with the formation of hydroxide surface groups and hydrogen bonds, which apparently block their catalytic activity in the Fenton redox cycle. The higher catalytic performance of AND + DND composite functionalized with copper ions makes it possible to detect two times lower concentrations of analytes (phenol and 4-chlorophenol) in comparison with the original composite. It is shown that the AND + DND + Cu composite provides a linear yield of the co-oxidation reaction product in a wide range of analyte concentrations (0.25–100 μM for phenol and 0.5–25 μM for 4-chlorophenol). Model experiments demonstrate the applicability of copper-functionalized composite as a reusable sensor for the determination of phenol in aqueous samples.