Exploring the peroxidase-like activity of 4Fe-Ni-B nanoparticles for analytical sensing

Natural enzymes, despite their superior catalytic proficiency, are frequently constrained by their environmental sensitivity and the intricacies associated with their extraction and preservation. Consequently, there has been a significant impetus in the scientific community to develop robust, economical, and accessible enzyme mimics. In this context, transition metal borides have risen to prominence as auspicious contenders, capitalizing on their distinctive electronic and catalytic attributes to replicate the functionalities of natural enzymes. In our present investigation, we report the synthesis of amorphous metal boride nanoparticles utilizing a straightforward chemical reduction approach conducted under refrigerated conditions. Notably, it is within this study that these nanoparticles are first showcased to exhibit inherent peroxidase-like activity, with the 4Fe-Ni-B composition demonstrating superior catalytic activity compared to other tested samples. Density functional theory (DFT) calculations have elucidated that the incorporation of nickel significantly bolsters the reactivity of 4Fe-Ni-B towards hydrogen peroxide (H₂O₂). This enhancement stems from a synergistic interaction between Ni²⁺ and Fe³⁺ ions, which expedites the reduction of Fe³⁺ to Fe²⁺, consequently augmenting the overall catalytic efficacy. To further broaden the applicative scope of these nanozymes, we have developed a colorimetric sensor for the rapid detection of H₂O₂ and glutathione (GSH), thereby underscoring the adaptability of transition metal borides in analytical chemistry.