Higher Efficiencies in Splitting Water and Carbon DioxideS. Himmelstein | August 31, 2017
North Carolina State University researchers have achieved marked efficiency increases in splitting water for hydrogen fuel production, and in splitting carbon dioxide to produce carbon monoxide for chemical manufacturing applications.
The revised water-splitting process uses an iron-doped barium manganese oxide catalyst to convert 90 percent of water into hydrogen gas. The redox catalyst is capable of splitting water at a significantly lower temperature and with a ten-fold increase in steam-to-hydrogen conversion relative to state-of-the-art solar-thermal water-splitting catalysts.
A nanocomposite of strontium ferrite dispersed in a chemically inert matrix of calcium oxide or manganese oxide was developed for the carbon dioxide splitting process. As the gas is run over a packed bed of particles composed of the nanocomposite, the material splits the carbon dioxide and captures one of the oxygen atoms. This reduces the carbon dioxide and leaves only carbon monoxide behind. Close to complete conversion of carbon monoxide was achieved at 900° C to 980° C with good redox stability.
The productivity and production rate of carbon monoxide were about seven times higher than those in state-of-the-art solar-thermal carbon dioxide-splitting processes, which are conducted at significantly higher temperatures. The process also uses the resulting oxygen to convert methane into syngas, which is itself a feedstock used to make fuels and other products.