Thermodynamically Controlled High-Pressure High-Temperature Synthesis of Crystalline Fluorinated sp³‑Carbon Networks

We report the feasibility of the thermodynamically controlled synthesis of crystalline sp³-carbon networks. We show that there is a critical pressure below which decomposition of the carbon network is favored and above which the carbon network is stable. Based on advanced, highly accurate quantum mechanical calculations using the all-electron full-potential linearized augmented plane-wave method (FP-LAPW) and the Birch–Murnaghan equation of state, this critical pressure is 26.5 GPa (viz. table of contents graphic). Such pressures are experimentally readily accessible and afford thermodynamic control for suppression of decomposition reactions. The present results further suggest that a general pattern of pressure-directed control exists for many isolobal conversions of sp² to sp³ allotropes, relating not only to fluorocarbon chemistry but also extending to inorganic and solid-state materials science

Relationships between the Charge–Discharge Methods and the Performance of a Supercapacitive Swing Adsorption Module for CO₂ Separation

We report a scaled-up supercapacitive swing adsorption (SSA) module with a novel radial gas flow design to separate CO₂ from a simulated flue gas mixture containing 15% CO₂ and 85% N₂. We define metrics that allow for a quantitative evaluation of the energetic and adsorption performance of SSA cycles, namely, the specific capacitance, the Coulombic efficiency, the energy efficiency, the energy loss, the sorption capacity, the electron efficiency, the energy consumption, the adsorption rate, and the time-energy efficiency. Using these metrics, we investigate the influence of different electrical charge–discharge methods on the energetic and adsorptive performance of the module and identify the most favorable charge–discharge method

Investigation of High-Pressure and Temperature Behavior of Surfactant-Containing Periodic Mesostructured Silicas

Surfactant-containing periodic mesostructured silica materials, namely SBA-16 and FDU-12, were studied under pressures between 1 and 4 GPa and temperatures between 100 and 400 °C. At 4 GPa crystallization of coesite can be achieved already at 200 °C. The mild transition of amorphous to crystalline silica is believed to be accomplished by the inbuilt hydroxyl groups present in the starting material. At 2 GPa the crystallization of quartz is accomplished at a temperature of 400 °C. Both quartz and coesite are obtained in nanocrystalline form