Microfluidic fuel cell architectures are presented in this thesis. This work represents the mechanical and microfluidic portion of a microfluidic biofuel cell project. While the microfluidic fuel cells developed here are targeted to eventual integration with biocatalysts, the contributions of this thesis have more general applicability. The cell architectures are developed and evaluated based on conventional non-biological electrocatalysts. The fuel cells employ co-laminar flow of fuel and oxidant streams that do not require a membrane for physical separation, and comprise carbon or gold electrodes compatible with most enzyme immobilization schemes developed to date. The demonstrated microfluidic fuel cell architectures include the following:​ a single cell with planar gold electrodes and a grooved channel architecture that accommodates gaseous product evolution while preventing crossover effects;​ a single cell with planar carbon electrodes based on graphite rods;​ a three-dimensional hexagonal array cell based on multiple graphite rod electrodes with unique scale-up opportunities;​ a single cell with porous carbon electrodes that provides enhanced power output mainly attributed to the increased active area;​ a single cell with flow-through porous carbon electrodes that provides improved performance and overall energy conversion efficiency;​ and a single cell with flow-through porous gold electrodes with similar capabilities and reduced ohmic resistance.

As compared to previous results, the microfluidic fuel cells developed in this work show improved fuel cell performance (both in terms of power density and efficiency). In addition, this dissertation includes the development of an integrated electrochemical velocimetry approach for microfluidic devices, and a computational modeling study of strategic enzyme patterning for microfluidic biofuel cells with consecutive reactions.