Room Temperature Oxidation of Ti₃C₂MXene for Supercapacitor Electrodes

Abstract

Two kinds of Ti 3 C 2 /TiO 2 hybrids were synthesized by room temperature oxidation methods, named as Ti 3 C 2 /TiO 2 -nanoparticles and Ti 3 C 2 /TiO 2 -nanowires, respectively. Effects of reaction time and concentration of NaOH solution on the microstructures and electrochemical performances of Ti 3 C 2 /TiO 2 composites were studied in details. When used as electrodes for supercapacitors, both Ti 3 C 2 /TiO 2 -nanoparticles and Ti 3 C 2 /TiO 2 -nanowires exhibit enhanced supercapacitive performances. The electrochemical measurement results show that the specific capacitances of Ti 3 C 2 /TiO 2 -nanoparticles and Ti 3 C 2 /TiO 2 -nanowires electrodes are 128 and 143 F/g at 2 mV/s, respectively, which are larger than that of Ti 3 C 2 MXene (91 F/g). Furthermore, after 6000 charge-discharge cycles at 5 A/g, 88% and 80% of the initial capacitances are retained for Ti 3 C 2 /TiO 2 -nanoparticles and Ti 3 C 2 /TiO 2 -nanowires, respectively. Therefore, this work not only enhances the understanding of the surface states and morphology structures of Ti 3 C 2 MXene at different reaction condition in the aqueous solutions, but also provides simple and facile ways to fabricate photocatalysts, 5-8 lithium-ion batteries 9-11 and supercapacitors. 12-14MXenes are produced by selective etching of "A" layers from M n+1 AX n (n = 1, 2, 3) phase, where M belongs to an early transition metal, A represents a IIIA or IVA element, and X is C and/or N. [15][16][17] The structures of the etched resultants are similar to the exfoliated graphite.15 Typically, MXenes are terminated by -OH, -O and/or -F surface groups (denoted as T x ), and so their general formula is M n+1 X n T x , 15,17,18 such as Ti 3 C 2 T x and Ti 2 CT x . MXenes show significant potential in energy storages benefiting from their layered structure, hydrophilic surfaces, outstanding electrical conductivity and excellent chemical stability. 10,12,13,[17][18][19][20] MXene-derived nanoribbons, formed in simultaneous oxidation and alkalization processes, also show high-performances in sodium and potassium ion batteries. 21 In addition, the electrochemical properties of MXenes and MXenesbased materials have been extensively investigated in aqueous 13,22,23 and nonaqueous electrolytes. 24,25 Notably, MXenes have been demonstrated to exhibit large pseudocapacitance, which is caused by ion intercalation between their two-dimensional nanosheets. 26,27 In order to satisfy the increasing strict requirements of energy storage devices, MXenes are motivated to exploit much better electrochemical performances. Recent studies reported that introduction of transition metal oxides into MXenes is an efficient way to improve the electrochemical properties in supercapacitors 28-31 and lithium-ion batteries 32,33 . Among the transition metal oxides, titanium dioxide (TiO 2 ) is one of the most widely investigated electrode materials, owing to its low cost, abundant availability and convenient synthesis in nanoscale sizes. [34][35][36][37] Many studies have reported different preparation...

High‐Performance Electrocatalytic Conversion of N2 to NH3 Using Oxygen‐Vacancy‐Rich TiO2 In Situ Grown on Ti3C2Tx MXene

“…Besides, from the O 1s spectra, the peak of OTi was greatly increased for the TiO 2 /Ti 3 C 2 T x than the Ti 3 C 2 T x . [57] The energy dispersive X-ray (EDX) characterization revealed that the atomic ratio of Ti/O in the TiO 2 /Ti 3 C 2 T x sample was higher than that in Ti 3 C 2 T x , again confirming the generation of the TiO 2 ( Figure S5, Supporting Information). The specific surface areas (SSA) of the Ti 3 C 2 T x and TiO 2 /Ti 3 C 2 T x samples were further characterized through the Brunauer-Emmett-Teller (BET) analysis ( Figure 1H).…”

Interaction of single- and double-stranded DNA with multilayer MXene by fluorescence spectroscopy and molecular dynamics simulations

“…The modes for Ti 3 C 2 T x MXene are located at 128, 219, 385, 618 and 711 cm À1 , comparable to previous reports. [55][56][57] The heterogeneity of the surface terminal groups affect the overall spectrum as a result of collaborative vibrations from surface and central Ti atoms, central C atoms, and the terminal groups -O, -OH and -F. The band at 128 cm À1 (E g ) is indicative of -F terminal groups from in-plane vibrations of surface Ti and C atoms. Out-of-plane stretching vibrations of surface Ti and C atoms give rise to the 219 cm À1 band as a result of -OH terminal groups.…”

A high-performance trace level acetone sensor using an indispensable V4C3Tx MXene

“…In addition, the specic surface area of the sample was further characterized by the Brunauer-Emmett-Teller (BET) method and N 2 adsorption/desorption isotherm analyses (Fig. S7 †), showing that as-exfoliated V 4 C 3 T x have a high BET surface area of 156 m 2 g À1 , which can compare with those of other MXenes, such as Ti 3 C 2 T x of 98 m 2 g À1 , 45 Ti 3 C 2 T x of 4.74 m 2 g À1 , 46 Ti 3 C 2 T x /TiO 2 nanowires of 56.45 m 2 g À1 , 46 etc.…”