PNNL

Abstract

We report the effect of solvent and electrolyte on the electrocatalytic oxidation of H2 using Ni(PCy2NR'2)2 (R = Bn, tBu) complexes. Optimized turnover frequencies of 46 and 51 s-1 were observed for each catalyst, respectively, under 1.0 atm H2 using nBuNH2 as the exogenous base utilizing different solvent/electrolyte combinations. The fastest observed rate for Ni(PCy2NBn2)2 was obtained in THF using 0.2 M [nBu4N][BF4] as the supporting electrolyte. In contrast, the fastest turnover frequency for Ni(PCy2NtBu2)2 was observed in fluorobenzene using 0.2 M [nBu4N][B(C6F5)4] as the supporting electrolyte. These observations, in conjunction with previous studies, indicate nitrile binding inhibits catalysis supported by Ni(PCy2NBn2)2. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.