Browsing by Author "Lokeshwar, H."

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    Deep-eutectic solvent-assisted green synthesis of MAX-phase Cr2AlC and its 2D-MXene derivative Cr2CTxtowards room-temperature detection of ammonia gas
    (Elsevier Ltd, 2025) Lokeshwar, H.; Lakshmi Praveen, L.; Mandal, S.; Shakti, N.
    This study explores the novel and eco-friendly chemical etching of bulk Cr2AlC MAX phases using a deep eutectic solvent (DES) mixture of choline chloride (ChCl) and anhydrous ferric chloride (FeCl3) to synthesize chromium carbide (Cr2CTx) MXene nanolayers. ChCl-FeCl3enables a fluoride-free transformation approach to synthesize Cr2CTxMXene via selective etching of aluminium interlayers, resulting in mixed surface terminations (-O, -OH, -Cl) confirmed from bond vibrations observed in FTIR transmittance spectra. Also, the FESEM micrographs confirm the formation of Cr2CTxnanolayers with successful cleavage of Cr2AlC MAX phase nanolaminates identified from a distinct red shift of D-band with the highest ID/IGratio peak intensity ratio, confirming the presence of high defect concentration in Cr2CTxMXene. The hydrothermally synthesized SnO2powders exhibiting a rutile tetragonal phase average particle size of 35.8 ± 0.8 nm were mixed with Cr2CTxto formulate screen-printable inks for the fabrication of Cr2CTx, SnO2, and their composite Cr2CTx-SnO2gas sensors. The addition of Cr2CTxdemonstrated a detrimental effect on the gas-sensing performance of the SnO2sensor, which was further supported from XPS analysis. However, the SnO2sensor recorded the highest gas-response of ?452 towards 100 ppm of ammonia gas among all sensors, highlighting the role of oxygen defects confirmed from photoluminescence spectra. This work paves the way for a novel and eco-friendly etching approach of MAX-phases and helps in their research towards the development of ultra-sensitive gas sensors. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.