Evaluation of iron containing biochar composites prepared by different preparation methods for H2O2 sensing

Abstract

Background The procedures employed to prepare the ferrous biochar samples, the iron salts utilized, and their quantities have an effect on the surface characteristics of the material and the types of iron that will develop on the surface.

Methods Iron containing biochar (Fe-BC) samples were prepared using three different preparation methods: Precipitation, Impregnation (IP) and Solid-state (SS). The iron content of the biochar (BC) was varied in a range from 6.5 to 21.0 wt. % by using a SS method that mechanically mixed FeCl3 and hazelnut shell (HS) in solid form.

Significant Findings The XRD, XPS and FT-IR results showed that the magnetite particles (Fe3O4) were mainly formed on the surface of all samples, but their content was strongly dependent on the preparation method and the amount of iron. Additionally, the formation of Fe2O3, Fe2C, FeCO3, and FeOOH species on the surface was determined. The highest surface area and microporosity were obtained for the Fe-BC sample prepared by IP (Fe-BC-IP):850 m2/g and 0.28 cm3/g, respectively. A novel and fast electrochemical sensing platform for the detection of H2O2 with a broad linear range (0.5-10 mM) and high sensitivity (621 µA mM−1 cm−2) was fabricated. The findings demonstrate that the non-enzymatic BC-IP sensor is a useful alternative for measuring H2O2.