Dr. Valdes-Morales, Hector

2024, Dr. Valdes-Morales, Hector, Annamalai, Arun, Annamalai, Kumaresan, Ayyanduarai, Nagarajan, Ravichandran, Ramya, Annamalai, Padmanaban, Elumalai, Sundaravadivel

Designing low-cost, effective and greener materials via a non-sophisticated strategy is most important for future research. Here, they made a new dual endeavor using carbon dots (CDs) as an environment protection probe for selective detection of environmental toxins, followed by the solid-state structural reformer to prepare NiMoO4 (NM) via mechanochemical-based solid grinding method. The prepared CDs, NM and NM-CDs combination is examined through various techniques. The prepared CDs selectively detect Cr6+, Ru3+, and Doxycycline independently. Also, in this work, a groundbreaking strategy is found to prepare morphology-tailored NM using CDs through a solid-state grinding method without adding any other toxic solvents or reagents. The CDs-induced NM-CDs (15) look like a 2D nano-sheet with enriched surface area compared to its bare NM. The fabricated electrode provides the highest capacitance value of 1947 F g−1, almost three times grander than the bare 1D rod-like electrode. Then, fabricated asymmetric supercapacitor NM-CDs (15)//AC system delivers a high energy density of 43.9 Wh Kg−1 at a power density of 684 W Kg−1. Overall, a single CDs serve multiple roles in the environment and energy applications with a greener structure tailoring agent and a better booster for re energy storage properties.

2023, Dr. Valdes-Morales, Hector, Annamalai, Kumaresan, Annamalai, Arun, Ravichandran, Ramya, Jeevarathinam, Anandhavalli, Annamalai, Padmanaban, Elumalai, Sundaravadivel

Nitrogen-doped carbon dots (N-CDs) possess outstanding photostability and interesting physicochemical and photochemical properties. Herein, we present cyan-emitting N-CDs that were fabricated through the treatment of salicylic acid with ethylene diamine using a simple microwave-assisted method. It was observed that the reaction produced N-CDs that strongly emitted cyan light with a quantum yield (QY) of 33%. The N-CDs were examined with the assistance of HR-TEM, XPS, XRD, FTIR, PL, and UV measurements. Due to the fluorescence enrichment effect caused by the N atoms in carbon dots, these N-CDs can be used as a fluorescent material for the detection of nitro-explosives and toxic metal cations. The addition of picric acid resulted in splendid quenching of the N-CDs, with a limit of detection (LOD) value of approximately 82.9 nM that was ascribed to the Fo ¨rster resonance energy transfer between the N-CDs and the nitro-aromatics. Furthermore, the powerful coordination between oxygen-rich moieties and N-CDs for the detection of Fe3+ and Hg2+ cations induced fluorescence quenching through photo-induced electron transfer and the inner-filter effect pathway, leading to the effective recognition of metal ions. The sensor probe exhibited a wide-ranging linear response with an LOD of approximately 30 nM for Fe3+ and 160 nM for Hg2+ ions. Thus, the as-prepared N-CDs can function as a fluorescence sensor, a secure portable information device, and a paper-based probe for detection in biological systems.