Predicted structural and mechanical properties of activated carbon by molecular simulation

Abstract

Combining the time-stamped force-bias Monte Carlo (tfMC) and simulated-annealing methods, different densities of activated carbon (AC) in different quench rates were constructed. Six AC models were constructed, corresponding to densities of 0.5, 0.7, and 1.3 g/cm3 and quench rates of 5 K per 30 tfMC steps and 5 K per 6000 tfMC steps, respectively. The structural properties of these models were examined, including porosity, specific surface area (SSA) and pore distribution. In uniaxial tensile simulation, the Young's modulus and the fracture of microstructures were also investigated. The specific surface area and Young's modulus are proportional to the density of AC, but the porosity and the main distribution of pore size are inversely related. The probability distribution of the ring size shows that six-atom rings translate to four- and five- atom ring during tensile simulation. The local shear strain analysis indicates that the fractures appear adjacent to the non-hexagonal ring defects and at the edge of the carbon wall frame in AC and will expand vertically along the tensile axis. This study not only constructs a structural prediction procedure of AC but also provides several detailed information of AC fracture.