Electrocatalytic hydrogen evolution by cobalt complexes of macrocyclic imine ligands

AEI 44

Xile Hu1, Bruce B. Brunschwig, bsb@caltech.edu2, Nathan S. Lewis1, and Jonas C. Peters1. (1) Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd. MC 127-72, Pasadena, CA 91125, (2) Molecular Materials Research Center, California Institute of Technology, Beckman Institute, 1200 E. California Blvd., Pasadena, CA 91125
Electrocatalytic hydrogen evolution in which protons are reduced to form dihydrogen at an electrode with the aid of a catalyst is an important method for hydrogen production. While platinum is currently the most efficient catalyst, there is a great need for molecular catalysts based on inexpensive and abundant materials. We have targeted Fe, Co, and Ni complexes as potential hydrogen evolving catalysts. To this end, we have synthesized a series of cobalt complexes of macrocyclic imine ligands and found that they indeed catalyze electrochemical hydrogen evolution at potentials in the range between -0.55 V to -0.20 V vs. SCE in acidic acetonitrile solutions. The potentials at which hydrogen evolution occurs are among the most positive values reported for molecular systems. We have studied the mechanism of the reaction and establish a correlation between the rates of hydrogen evolution and the Co(II/I) potentials of the catalysts.
 

Academic Employment Initiative
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Academic Employment Initiative

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006