Photocatalysis using light-emitting diodes could reduce the amount of carbon dioxide emitted by industrial chemical processes. Already as a teenager, Chern-Hooi Lim was worried about the consequences that climate change would have on his generation. Now armed with a doctorate in chemical engineering, Lim leads New Iridium, a company in Boulder, Colorado that hopes to harness the power of light to remove a significant portion of the greenhouse gas carbon dioxide from chemical manufacturing processes—and even some of it into useful products. (Neil Savage)