Confined Molecular Dynamics for Suppressing Kinetic Loss in Sugar Fuel Cell

We corroborated substantial suppression of kinetic loss in sugar fuel cell owing to microscopic molecular dynamics at nanoporous electrodes. When electrochemical reaction is sluggish, exchange current density (j0) is governed by how often the reactants encounter the surface of catalyst. This highly frequent interaction between reactant and electrode surface can be achieved by confined molecular dynamics in nanoporous electrode. Using sucrose molecule as an oxidant fuel, the performance of nanoporous Pt (L2-ePt) with pore size of 1 to 2 nm was compared with that of thin layer of Pt nanoparticles (Pt NPs) that was electrodeposited on a polished Pt surface to exclude the effects of crystalline facets and defects. As sucrose is bulkier and less adsorptive than glucose and undergoes sluggish electrochemical oxidation, sucrose oxidation substantially benefits from the confined molecular dynamics at nanoporous electrode. The current density (JRSA) normalized by real surface area (RSA) of sucrose oxidation at L2-ePt was higher than Pt NPs. In fuel cell operation, open circuit voltage of L2-ePt was measured to be 0.593 V, 4.4 times higher than Pt NPs and j0 significantly increased at L2-ePt. Moreover, maximum power density (PRSA) of L2-ePt was much higher by a factor of 15.7 than Pt NPs.