MXene-based nanostructures for electrochemical CO oxidation
Date
2024
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Abstract
2-D MXene based nanostructure owns several unique physicochemical and catalytic properties. Herein, this research used MXene (Ti3C2Tx) for the electrochemical COoxid reaction experimentally for the first time. This work divided to two sections, the first is using mono metal decorated Ti3C2Tx and the second using binary metals decorated Ti3C2Tx to investigate and compered the electrochemical COoxid reaction activity of mono and binary metals with Ti3C2Tx. At first, Ti3C2Tx (TX=OH, O, and F) well-ordered and highly exfoliated 2-D nanosheets used as substrate for the NPs growth and prepared via the selective chemical etching and delamination of MAX phase (Ti3AlC2) with sonication assistance to form Ti3C2Tx nanosheets. After that, Mono and binary metals were prepared via using a facile method by in situ impregnation of Pd or Pt or both salts with Ti3C2Tx in aqueous medium under sonication without using reducing agent or surfactant. The as prepared Pt/Ti3AlC2, Pd/Ti3AlC2, and PtPd/Ti3AlC2 composition and structure were characterized by the scanning electron microscope (SEM), Energy Dispersive X-Ray Analyzer (EDX), the transmission electron microscope (TEM) equipped with high-angle annular dark-field scanning transmission electron microscopy (HAADF-SEM), energy dispersive spectrometer (EDS), The X-ray photoelectron spectroscopy (XPS) spectra and The X-ray diffraction patterns (XRD). The electrochemical COoxid activity were explored using The cyclic voltammogram (CVs), linear sweep voltammogram (LSV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) for all prepared of different samples using Gamry electrochemical analyzer using a three-electrode system contains a Pt wire (counter electrode), Ag/AgCl (reference electrode), and glassy carbon ((3mm) WE) in an aqueous solution saturated with CO of three electrolytes acidic (0.1 M HClO4), neutral (0.5 M NaHCO3) and basic (0.1M KOH) at different sweep rate. The first study showed the electrochemical activity and effect of mono metals NPs of Pd/Ti3C2Tx compared with metal-free Ti3C2Tx in acidic electrolyte, Interestingly, Ti3C2Tx displayed poorer COoxid activity and the integrating of Pd NPs enhance the activity, ascribed to the combination between outstanding physical and chemical properties of Ti3C2Tx and the catalytic advantages of Pd. In contrast, the second study the electrochemical COoxid activity for binary compared with mono NPs decorated Ti3C2Tx. Results showed PdPt/ Ti3C2Tx was substantially superior to Pd/ Ti3C2Tx, Pt/ Ti3C2Tx, and metal-free Ti3C2Tx in three electrolytes experimentally, owing to the electronic and synergetic effect of PdPt and physiochemical properties of Ti3C2Tx. This study may pave the way for the employment of Ti3C2Tx in electrochemical C
Description
A research report submitted in partial fulfilment of the requirements for the degree Master of Science to the Faculty of Science, School of Chemistry, University of the Witwatersrand, Johannesburg, 2023
Keywords
Electrochemical, MXene