Hydrogen evolution at low overpotentials

Abstract

Global energy demands motivate us to consider whether technol. valid solns. to renewable energy sources can be found. Chemists have for decades wanted to mimic biol. photosynthesis, but the vast no. of scientific and technol. challenges assocd. with such an endeavor have precluded the development of chem. systems that are efficient. Our belief is that photocatalysts for water-splitting, interfaced with a photoelectrode membrane, may some day provide the soln. to clean and efficient, carbon-free fuel from sunlight. The types of catalysts that might in principle efficiently mediate hydrogen or oxygen evolution are chem. distinct and thus need to meet independent design criteria. A crit. chem. question therefore becomes: How can we generate efficient mol. catalysts for each of the half-cell reactions of water-splitting, and how can we get these catalysts to work in concert with one another, and also with a photoelectrode membrane, to generate storable fuel form sunlight and water Moreover, how can we redirect the protons and electrons derived from the photooxidn. of water to fix carbon substrates such as CO2Our group has been actively engaged in a collaborative effort between several universities and national labs, supported by the NSF, called 'Powering the Planet'. The goal of this collaborative center is to meet the fundamental science challenges assocd. with each element of a photosynthetic app. As our group's expertise pertains to homogeneous catalysis, we have been exploring promising catalyst systems that mediate proton redn. to hydrogen at unusually low overpotentials.