An efficient solar process for the one-step conversion of CO2 and H2O to C5+ liquid hydrocarbons and O2 would revolutionize how solar fuel replacements for gasoline, jet, and diesel solar fuels could be produced and could lead to a carbon-neutral fuel cycle. A team of University of Texas at Arlington chemists and engineers have demonstrated that this reaction is possible in a single-step process by operating the photocatalytic reaction at elevated temperatures and pressures. The process uses cheap and earth-abundant catalytic materials, and the unusual operating conditions expand the range of materials that can be developed as photocatalysts. Whereas the efficiency of the current system is not commercially viable, it is far from optimized and it opens a promising new path by which such solar processes may be realized. This simple and inexpensive new sustainable fuels technology could potentially help limit global warming by removing carbon dioxide from the atmosphere to make fuel. The process also reverts oxygen back into the system as a byproduct of the reaction, with a clear positive environmental impact. http://www.eurekalert.org/pub_releases/2016-02/uota-pop022216.php Paper: http://www.pnas.org/content/early/2016/02/17/1516945113
As both CO2 and water hotter than 100C are gases, this would be an ideal application of my mass flow solar absorber, a very efficient solar thermal system (can achieve very high temperature with essentially zero IR re-radiation losses). See full details about it in long expired US patent 4033118. The patent does discuss chemical processing but main focus was on getting high conversion (to mechnaical work / power generation) efficiency. Solar thermal power efficiency is Carnot limited. If that is high in other systems then the IR re-reaidation losses are great too.
I suppose the key thing is how the efficiency and environmental impact of this process compares with growing plants and harvesting them for biofuel. From what the authors say, they are really at the proof of concept stage, rather than claiming any special advantage relative to conventional photosynthesis.
