Facile engineering of gadolinium cobaltite anchored on functionalized carbon black as dynamic electrocatalyst for ultra-sensitive detection of nitroaromatic drug

There has been a significant increase in the production and use of antibiotic drugs. However, the overuse and improper disposal of nitro-based antibiotics pose a significant threat to human health and the ecosystem. Specifically, the residues of antibiotic drugs such as nitrofurantoin (NFT) are dangerous to public health and pose a threat to the environment. In this study, we prepared a novel nanocomposite consisting of gadolinium cobaltite embedded functionalized carbon black (GdCoO3/f-CB) via a simple hydrothermal technique and utilized this nanocomposite as an electrode material for the electrochemical detection of NFT. The structural and morphological properties of the GdCoO3/f-CB nanocomposite was analyzed using a range of techniques, including XRD, Raman, XPS, EDX-Mapping, and HR-TEM. The electrocatalytic activity of the GdCoO3/f-CB nanocomposite was investigated using both CV and DPV techniques for the detection of NFT. Our results demonstrated that the prepared GdCoO3/f-CB nanocomposite delivered the excellent activities toward the detection of NFT at an extremely low limit of detection (LOD) of 2 nM and exhibited high sensitivity of 31 μA·μM-1·cm-2. Additionally, the proposed NFT sensor using GdCoO3/f-CB nanocomposite provided excellent reproducibility, repeatability, and selectivity, even in the presence of interfering molecules such as metal ions, biomolecules, and similar nitro compounds. These findings suggest that the GdCoO3/f-CB nanocomposite provides significant potential for the electrochemical detection of antibiotic drug residues for public health and the environment.

First-Principles Investigation of Graphene and Fe2O3 Catalytic Activity for Decomposition of Ammonium Perchlorate

The employment of catalysts is an effective way to improve ammonium perchlorate (AP) decomposition performance during the combustion of composite solid propellants. Understanding the micromechanism of catalysts at the atomic level, which is hard to be observed by experiments, can help attain more excellent decomposition properties of AP. In this study, first-principles simulations based on density functional theory were used to explore the effect of the graphene catalyst and iron oxide (Fe₂O₃) catalyst on AP decomposition. Considering the transfer of a H atom during AP decomposition, the most stable adsorption sites for aforementioned catalysts were found: the top of the C atom of the graphene surface with the adsorption energy of -0.378 eV and the top of the Fe atom of the Fe₂O₃ surface with the adsorption energy of -1.596 eV. On the basis of adsorption results, our transition state calculations indicate that, in comparison to control groups, graphene and Fe₂O₃ can reduce the activation energy barrier by ∼19 and ∼37%, respectively, to promote AP decomposition with a transfer process of a H atom on the catalyst surface. Our calculations provide a way for explaining the micromechanism of the catalytic activity of graphene and Fe₂O₃ nanocomposites in AP decomposition and guide experimental applications of graphene and Fe₂O₃ for catalytic reactions.