Mathematical Modeling of Solar-Fuel Generators

A solar-fuel generator is a multicomponent device composed of light absorbers, electrocatalysts, membranes, and electrolytes in a specific system geometry. The overall solar-to-fuel conversion efficiency of such a system depends on the performance and materials properties of the individual components as well as the design of the system. In this talk, efforts in the Joint Center for Artificial Photosynthesis (JCAP) aimed at the continuum-scale modeling of these various components will be presented. In particular, the tradeoffs between the transport phenomena, kinetics, and photon capture will be detailed for different geometries and conditions. For example, the use of optically concentrating lenses can result in efficiency gains and lower cost systems, although the increased temperatures have both beneficial (e.g., transport properties and kinetics) and detrimental (light absorber efficiency and solvent stability) impacts that are ideally optimized through modeling. In addition, applications of the modeling framework to both hydrogen generation via water splitting and fuel formation via carbon reduction will be discussed, where the product distribution of the latter is heavily influenced by the local electrode overpotential.