As highlighted by the U.S. Department of Energy Solar Energy Technologies Program, “solar technologies diversify the energy supply, reduce the country's dependence on imported fuels, improve air quality, and offset greenhouse gas emissions”. The efficient conversion of solar energy into chemical energy (solar fuels), through processes such as photo-catalytic water splitting and CO2 reduction, is critically important for the development of sustainable, long-term solutions to society's energy and environmental problems. These and other photo-electro-chemical processes require the development of photo-electro-catalysts that efficiently make use of the solar spectrum and activate critical chemical transformations with low over-potential losses. Photo-electro-catalysts have a combination of thermal, electrical and solar stimuli, each of which must be investigated to provide insights into the performance and ultimately the design of novel photo-electro-catalysts.
Using a multi-scale approach, which combines a number of experimental and theoretical tools, we have begun to investigate and understand these complex systems. Several case studies are presented, including theoretical investigations of metal/oxide electro-catalysis (focusing on high temperature solid oxide fuel cells) and experimental studies of photo-catalytic reactions (photochemical water splitting and decomposition of organic molecules).