Carbon materials with large exposed surfaces and heteroatom doping have great potential in suppressing the shuttle effect in Li–S batteries. In this study, crosslinked triazine frameworks were successfully utilized to synthesize heteroatom-doped carbon nanosheets utilizing g-C3N4 nanosheets as the hard template and porogen. Characterization studies show that the nanosheets were highly crinkled and interconnected with a large surface area (1060 m2 g−1) and pore volume (2.14 cm3 g−1), and with highly dispersed N, O and S. After coating them on commercial Celgard separators, batteries with the modified separators showed a low self-discharge and an improved rate performance even at 4 C. At 0.5 C, the initial discharge capacity was 1240 mA h g−1 with a capacity decay of 0.059% per cycle for over 1000 cycles. Moreover, excellent cycling performances at 2 C for 500 cycles were also achieved. The excellent performance can be attributed to the large surface area and porous structure of NOS-C, the superior wettability toward the electrolyte, enhanced Li+ diffusion, strong interactions between polysulfides and doped atoms, and the accelerated redox kinetics of polysulfides.
Graphene-based nanocomposite films (NCFs) are in high demand due to their superior photoelectric and thermal properties, but their stability and mechanical properties form a bottleneck. Herein, a facile approach was used to prepare nacre-mimetic NCFs through the non-covalent self-assembly of graphene oxide (GO) and biocompatible proteins. Various characterization techniques were employed to characterize the as-prepared NCFs and to track the interactions between GO and proteins. The conformational changes of various proteins induced by GO determined the film-forming ability of NCFs, and the binding of bull serum albumin (BSA)/hemoglobin (HB) on GO’s surface was beneficial for improving the stability of as-prepared NCFs. Compared with the GO film without any additive, the indentation hardness and equivalent elastic modulus could be improved by 50.0% and 68.6% for GO–BSA NCF; and 100% and 87.5% for GO–HB NCF. Our strategy should be facile and effective for fabricating well-designed bio-nanocomposites for universal functional applications.
The catalytic oxidation of alcohols is an important transformation in the chemical industry. Carbon materials with a large surface area and N doping show great promise as metal-free catalysts for the reaction. In this study, a rich N-containing covalent triazine framework polymerized by cyanuric chloride and p-phenylenediamine was used to synthesize N-doped porous carbon with the assistance of a pore-forming agent—NaCl. First, the mass ratio of the polymer/NaCl was optimized to 1:9. Then, the influence of the pyrolysis temperatures (700–1000 °C) on the materials was studied in detail. It was found that the carbon materials were gradually exfoliated by molten salt at high temperatures. XRD and Raman characterizations showed them with a certain graphitization. The optimal doped carbon CNN-1-9-900 achieved the highest surface area of 199.03 m2g−1 with the largest pore volume of 0.29 cm3g−1. Furthermore, it had a high N content of 9.9 at% with the highest relative proportion of pyridinic/graphitic N. Due to the synergistic effect between the surface area and pyridinic/graphitic N, CNN-1-9-900 showed the best performance for benzyl alcohol oxidation with TBHP at moderate conditions, and the process also worked for its derivatives.
Ti 3 C 2 T x MXene/Cu-MOF composites with different MXene contents (3.3%, 6.7%, and 13.3%) were synthesized and showed the best equilibrium adsorption capacity of 87.4 mg g −1 .
1 January 2024 in International Journal for Numerical Methods in Fluids