In situ generation of a Ti3C2Tx (Tx = F, O and OH) MXene decorated CuO nanocomposite with extraordinary catalytic activity for TKX-50 thermal decomposition

Abstract

In this work, CuO was in situ generated on the Ti₃C₂T_x MXene surface by using electrostatic self-assembly between the positively charged Cu²⁺ and the negatively charged nanosheet Ti₃C₂T_x MXenes, thereby preparing a highly reactive I-Ti₃C₂T_x/CuO composite precursor. After electrostatic self-assembly, nano CuO particles are deposited on the surface of Ti₃C₂T_x MXenes by controlling the alkali content and the droplet acceleration of the solution, and the final samples are obtained using the vacuum cold drying technology. The whole process requires no high temperature calcination, which can effectively prevent Ti₃C₂T_x from being oxidized at high temperature, thus leading to achieve an effective comparison of the obtained final samples with graphene oxide (GO). The results of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), EDS mapping and X-ray photoelectron spectroscopy (XPS) showed that the in situ generation method successfully led to the dense formation of CuO on the MXene surface and even development of CuO lamellar structures, while the mechanical mixing method resulted in poor CuO distribution on MXene. The catalytic properties of I-Ti₃C₂T_x/CuO for the thermal decomposition of TKX-50 were studied using thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC). The addition of 4 wt% I-Ti₃C₂T_x/CuO can effectively reduce the pyrolysis peak temperature of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) to 33.9 °C and increase the heat release by 328 J g⁻¹, which is superior to that of I-GO/CuO (CuO is generated in situ on the GO surface). The possible catalytic mechanism that I-Ti₃C₂T_x/CuO under heating conditions can promote H⁺ transfer of the ionic bond between hydroxylamine and bistetrazole more easily further accelerates the early generation of gas products. This work broadens the application of MXene composites and also gives new inspiration in the field of energetic materials.