Progress towards a synergistically integrated, scalable solar fuels generator

The development of an artificial photosynthetic system involves obtaining desired functionalities on the nanoscale. A viable blueprint for an artificial photosynthetic system involves two complementary, current-matched and voltage-adding photosystems, in conjunction with two different catalysts: one to oxidize water, and the other to reduce either water and/or carbon dioxide to solar fuels. Recent progress towards a robust, efficient, inexpensive and safe solar-fuels generator provides an example of nanoscale materials-by-design. The light-absorbing semiconductors have been designed and grown as high-aspect-ratio microwires which simultaneously allow minimization of ionic transport pathways, sufficient depth for light absorption in the semiconductor, efficient collection of charge carriers, and high surface areas for catalyst loading. Non-noble-metal catalysts for the redox reactions have been discovered, and methods for protecting the semiconductors against corrosion have been developed.