Atomistic Analysis of Proton Diffusivity at Enzymatic Biofuel Cell Anode

This paper investigates the proton diffusion phenomenon between the anode catalyst and the electrode in an enzymatic bio-fuel cell. The bio-fuel cell uses enzymatic organism as the catalyst instead of the traditional noble metal, like platinum. The fuel is normally the glucose solution. The fuel cell is membrane-less and produces electricity from the reaction taken place in the organism. When the biochemical reaction occurs, the protons and electrons are released in the solution. The electrons are collected by the electrode plate and are transported to the cathode through an external circuit, while the protons migrate to the cathode by the way of diffusion. Unfortunately, protons are easy to dissipate in the solution because the enzyme is immersed in the neutral electrolyte. It is an important issue of how to collect the protons effectively. In order to investigate the diffusion process of the protons, a molecular dynamics simulation technique was developed. The simulation results track the transfer motion of the protons near the anode. The diffusivity was evaluated from the trajectory. The research concludes that the higher the glucose concentration, the better the proton diffusivity. The enzyme promotes the electrochemical reaction; however, it also plays an obstacle in the proton diffusion path.