Hydration and Proton Transfer processes in Sulfonated Nata De C°Co Membrane with Density Functional Theory

摘要

Direct Methanol Fuel Cells (DMFCs) is one of the most promising alternative energy resources to meet human energy needs. DMFCs is fuel cells that use polymer membranes as the electrolytes to transfer the protons from anode to cathode. The characteristics of those two types of membranes in ion exchange capacity (IEC) and degree of swelling (swelling) have shown a very important role of water in the proton transfer. However, the mechanism of interaction between the repeating units of the polymer with water molecules has not been studied in depth. Computational methods can be used to study such interactions as well as the transfer of protons. To examine the transfer of protons in the membrane, studies of computing via electronic structure calculations, geometry optimization, interaction inter/intra molecular, as well as the hydration process and transfer of protons in the sulfonated nata-de-coco membranes (NDCS) has been conducted in this work. All calculations were performed using DFT with B3LYP functional and basis set 6-311G(d). The repeating units of the membranes were optimized (n=1,2,...,5), to obtain the structure with minimum energy. The optimized structure was then interacted with one water molecule in the same position to study the effect of chain length on its interaction strength with water molecules. The thermodynamic and proton diss°Ciation parameters was calculated by adding n water molecules (n=1,2, …,10) to determine the hydration process and the proton transfer on the membranes.