Synthesis of Ti₃C₂T_x MXene from the Ti₃AlC₂ MAX phase with enhanced optical and morphological properties by using ammonia solution with the in-situ HF forming method

Abstract

Liquid phase exfoliation of Ti3C2Tx MXene using LiF/HCl mix, forming HF in situ, has been modified by the addition of NH4OH. The base assisted dilution and extraction of MXene enables a quick control over pH and improves the structural, morphological and optical properties of the compound. The formation of a buffer compound NH4F, reduces the oxidation on the surface of MXene and etches off the residual MAX phase, by attacking Al. The structural features of the prepared NH4OH added Ti3C2Tx MXene are remarkably better than the HF etched samples, with the characteristic MXene peak in XRD being emphasized in the former. The addition of ammonia solution improves the milder in situ HF etching technique, by giving the characteristic open accordion structure to the compound, making the compound easy to delaminate and more stable against oxidation in ambient atmosphere.

Carbon Dot/Ti3C2Tx MXene Hybrid on Carbon Cloth as a Flexible and Binder‐Free Supercapacitor Electrode with Commercial Scale Mass Loading

“…A detailed discussion of the peak shifts observed in the XRD has been conducted elsewhere. [47] The purity of the prepared sample was assessed using the Equation ( 6) put forth by Mashtalir et al: [82] y…”

“…MXene synthesized by in situ HF forming technique was modified by base‐assisted washing using NH 4 OH, to obtain MXene having enhanced structural, optical, and electronic features. [ 47 ] The X‐ray absorption spectra (XAS) of the pristine (P MX) sample's Ti L‐edge was compared with that of the modified sample (MX). The XAS spectra obtained are given in Figure S1, Supporting Information.…”

“…[47] The postetching solution was washed using 25% ammonia solution when a pH of 6 was achieved, as ammonia solution improves the overall properties of the material. [47] Nitrogen-doped CD was prepared as per previous reports with slight modification using citric acid and ethylenediamine precursors, via hydrothermal synthesis followed by dialyzation. [64,65]…”

“…[ 46 ] Hence in the present work, the material was synthesized via a base‐assisted in situ HF forming technique, instead of a direct HF‐assisted etching technique, to obtain MXene with more redox active functional groups, better structural, morphological, and optoelectronic properties. [ 47 ] However MXenes are limited by their tendency to restack via van der Waal's force. Different nanohybrids consisting of metal oxide/MXene combinations have been used to tackle this issue and to prevent the collapse of 2D layered structures.…”

A simple, efficient, fluorine‐free synthesis method of MXene/Ti3C2Tx anode through molten salt etching for sodium‐ion batteries

“…In recent years, Li et al 25 have introduced a Lewis acidic molten salt etching method as an alternative to traditional HF‐based solvents for MXene synthesis. It is worth noting that etching MXene with a surficial “–F” can result in insufficient ion diffusion, leading to suboptimal performance of energy storage devices 26,27 . However, this limitation can be overcome by employing the molten salt method.…”