Graphene-Immobilized fac-Re(bipy)(CO)3Cl for Syngas Generation from Carbon Dioxide.

We report the synthesis of fac-M(4-amino-bipy)(CO)3X (M = Mn and X = Br or M = Re and X = Cl, bipy = 2,2'-bipyridine), their immobilization on graphene oxide (GrO) via diazonium grafting, and the use of Re-functionalized GrO for electrocatalytic syngas production. Infrared spectroscopy (IR), X-ray absorption fine structure (XAFS) spectroscopy, and electrocatalysis indicated successful grafting of the Re catalyst onto GrO. The Re-functionalized GrO was then deposited onto a glassy carbon electrode (GCE) for CO2 reduction. Investigation of the Re-functionalized GCE for syngas production was performed in a CO2 saturated acetonitrile solution with 3.1 M H2O as the proton source and 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte. Cyclic voltammetry (CV), controlled potential electrolysis (CPE), and gas chromatography (GC) were employed to determine its CO2-to-CO conversion performance. The Re catalyst shows a turnover frequency (TOF) for generating CO up to 9.38 s-1 with a CO: H2 ratio of 5:3.