Cobalt Schiff-base complexes for electrocatalytic hydrogen generation

Abstract

Two cobalt(III) complexes containing inexpensive Schiff-base ligands have been found to be active for proton reduction at low overpotentials. The dinitro and tetranitro derivatized Schiff-base complexes show catalytic activity at −0.96 V and −1.1 V vs. Fc⁺/Fc, respectively, resulting in overpotentials of 120 mV and 280 mV. Foot-of-the-wave analysis is used to examine the kinetic properties of these complexes, yielding a theoretical TOF_max of up to 4100 s⁻¹. Experimental TOFs of 7 s⁻¹and 3 s⁻¹ are observed. Catalytic Tafel plots are also presented in order to benchmark the relationship between turnover frequency and overpotential.