Researchers at the Swedish KTH Royal Institute of Technology have created a catalyst that can break water into oxygen and protons (which become hydrogen) at a turnover rate of 300 oxygen molecules per second per catalyst. The rate sets a world record for "turnover frequency," and represents an important breakthrough in artificial photosynthesis.
A major branch of research into harvesting light energy targets producing hydrogen from water directly with light, instead of generating electricity and then losing a lot of efficiency breaking up oxygen electrolytically. The speed of the artificial process remained an obstacle, with the best known artificial catalysts performing a hundred times more poorly than nature's process.
But the KTH group's record-setting turnover frequency of 300 lands squarely in the middle of the natural rate of 100 to 400 turnovers per second. Their catalyst consists of a complex molecule in which the metallic atom Ruthenium lies embedded in a plane of bipyridine dicarboxylic acid with two isoquinolines projecting above and below the plane. The catalyst is "rationally designed," using biomimicry of natural photosynthesis to develop an efficient artificial process.
Lead researcher and Organic Chemistry Professor Licheng Sun says of the work:"Solar is the best hope for renewable energy". And we may not have to wait that long; Professor Sun emphasizes:
I’m convinced that, within ten years, this type of research will lead to technology that’s inexpensive enough to compete with coal.
The research appears in the journal Nature Chemistry under the title "A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II."