Artificial Photosynthesis, Bio-inspired Design

Artificial photosynthesis is a dream technology that mimics a natural leaf, converting water and carbon dioxide into fuels with sunlight. But before this technology can take flight, scientists will have to solve a fundamental plumbing problem: how to gather molecules of fuel from microscopic reaction sites to pipes that will pour it out by the gallon. Here again, researchers are taking a cue from nature. Following the same mathematical rules of "self-similarity" that govern the fractal shapes of snowflakes or determine the structure of blood vessels and capillaries, scientists at Berkeley Lab have shown how a single pipe can be subdivided into a network of microfluidic channels, or the reverse. This is the micro-plumbing needed to carry water and carbon dioxide to catalytic sites, where sunlight will split water, and hydrogen and oxygen are then channeled off separately; additional reactions can form hydrocarbon chains further downstream. Kenny Lee, a graduate student in the Department of Mechanical Engineering at UC Berkeley, hit upon the "self-similarity" solution while working in the Fluid Mechanics Laboratory of Ömer Savas. Both researchers are Berkeley Lab members of the Prototyping Group within the Joint Center for Artificial Photosynthesis (JCAP), a DOE Energy Innovation Hub.