Charge-Transfer and Photocatalytic Hydrogen Production By Hydrogenase Photobiohybrids

Hydrogenases are metalloenzymes that catalyze H₂ activation at of ≥10⁴ s^-1 using base metals (Fe, Ni, S) and a polypeptide framework. Understanding the structural properties of hydrogenases, including the cataltyic site cofactors, has provided inspiration for designing highly functional synthetic catalysts. We have been invetigating hydrogenase structure-function and use as electrocatalysts on nanostructured electrodes, and photocatalysts in solution-phase assemblies with nanomaterials. In both cases, the hydrogenase provides the catalytic power for converting photo(electro)chemical energy into H₂. The chemistry of (nano)materials can be used control their physical and molecular properties over a wide-range of energy and size scales for integrating with the catalytic and sturctural propeties of hydrogenases. As a result, the biohybrid complexes are being investigated as models to determine how material compositions, charge-transfer interfaces and bulk properties affect the mechanisms that support photocatalysis. A summary of our recent progress in this area of research will be presented.