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We report the intercalation of polyacrylonitrile nanoparticles in Ti3C2Tx MXene layers through simple sonication. The use of polyacrylonitrile, which was synthesized via radical polymerization, offered dual benefits: (1) It increased the interlayer spacing of MXene, thereby exposing more surface area and enhancing ion transport channels during charge and discharge cycles, and (2) Integrating MXene with polyacrylonitrile enables the creation of a composite with conductive properties, following percolation principle. X-ray diffraction analysis showed an increase in the c-lattice parameter, indicative of the interlayer spacing, from 22.31 Å for the pristine MXene to 37.73 Å for the MXene−polyacrylonitrile composite. The intercalated polyacrylonitrile nanoparticles facilitated the delamination by weakening the interlayer interactions, especially during sonication. Electrochemical assessments revealed significant improvement in the properties of the MXene−polyacrylonitrile composite compared to the pristine MXene. The assembled asymmetric device achieved a good specific capacitance of 32.1 F/g, an energy density of 11.42 W h/kg, and 82.2% capacitance retention after 10,000 cycles, highlighting the practical potential of the MXene−polyacrylonitrile composite. 

The novel material, one-dimensional lepidocrocite (1DL) titanate, is attracting industrial and scientific interest because of its applicability to a wide range of practical applications and its ease of synthesis and scale up of production. In this study, we investigated the CO2 adsorption capability and pore structures of 1DL freeze-dried and lithium chloride washed air-dried powders. The synthesized 1DL was characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Using the constant-volume method, CO2 gas adsorption revealed that the 1DL exhibits type IV adsorption–desorption isotherms. The heats of adsorption obtained from the adsorption branches are lower than those obtained from the desorption branches. Brunauer–Emmett–Teller (BET) analysis, using N2 gas adsorption isotherms at 77 K showed that 1DL possesses 80.2 m2/g of BET specific surface area. Nonlocal density functional theory analysis indicated that two types of pores, meso-pores and ultramicro pores, exist in the 1DL freeze-dried powders. This work provides deep insights into the pore structures and CO2 adsorption mechanisms of 1DL powders. 

Two-dimensional materials based on transition metal carbides have been intensively studied due to their unique properties including metallic conductivity, hydrophilicity and structural diversity and have shown a great potential in several applications, for example, energy storage, sensing and optoelectronics. While MXenes based on magnetic transition elements show interesting magnetic properties, not much is known about the magnetic properties of titanium-based MXenes. Here, we measured the magnetic properties of Ti3C2Tx MXenes synthesized by different chemical etching conditions such as etching temperature and time. Our magnetic measurements were performed in a superconducting quantum interference device (SQUID) vibrating sample. These data suggest that there is a paramagnetic-antiferromagnetic (PM-AFM) phase transition and the transition temperature depends on the synthesis procedure of MXenes. Our observation indicates that the magnetic properties of these MXenes can be tuned by the extent of chemical etching, which can be beneficial for the design of MXenes-based spintronic devices.