A novel method for synthesizing manganese dioxide nanoparticles using diethylenetriamine pentaacetic acid as a metal ion chelator

Abstract Manganese dioxide nanoparticles (MnO2 NPs) have been typically synthesized using polymers as reducing agents to reduce permanganate and/or as coating agents to increase colloidal stability. However, thus far, there have been no reports regarding methods for preparing MnO2 NPs using permanganate and only metal ion chelator. Herein, we proposed a new method for synthesizing MnO2 NPs by directly reducing permanganate using diethylenetriamine pentaacetic acid (DTPA) as a metal ion chelator. MnO2 NPs were synthesized by the simple reaction of DTPA as a chelating and reducing agent with different molar ratios of potassium permanganate (KMnO4). The synthetic DTPA/MnO2 produced nano-sized particles with sizes ranging from 208 nm to 241 nm, with negatively charged surfaces. The DTPA/MnO2 NPs that were synthesized at a molar ratio of 1:4 (DTPA:KMnO4) exhibited the highest stability and storage stability in deionized water. Further, the DTPA/MnO2 NPs could be rapidly degraded in the presence of hydrogen peroxide and simultaneously generate oxygen. Thus, in this study, we report the successful synthesis of novel MnO2 NPs synthesized using the metal ion chelator DTPA. Moreover, we believe that this NP-synthesis method will be widely applied to synthesize new types of MnO2 NPs using various metal chelators.