(530f) Solar Photoelectrocatalysis for Production of Fuels and Chemicals: Is There a Cost-Effective Path Forward?

The use of sunlight and man-made photoelectrocatalysts to facilitate useful endothermic electrosynthetic reactions has been under investigation for decades. Although the fundamental processes involved are well known and highly efficient semiconductor device structures have been demonstrated, there is presently no cost-effective material system that has sufficient solar-to-chemical conversion efficiency for use in any practical commercial system. The design and synthesis of nanostructured photoelectrocatalysts from earth abundant materials including iron and copper containing oxides is under investigation. Pure phase hematite is a Mott insulator with poor conductivity and overall poor intrinsic performance. Results using density functional theory inspired substitutional doping of iron oxide to improve the internal quantum efficiency will be presented together with an overview of recent work with iron and copper oxides, sulphides, and selenides where nanostructures have been used to minimize the charge transfer path length. Relative comparisons in performance of copper and iron based oxides will be given. The economic constraints of a photoelectrochemical solar-to-chemical process will be outlined and conceptual proposals presented for practical systems making use of low cost renewable feedstocks that may have significant impact on the basic materials investigated in the future.