Kinetic and structural studies, origins of selectivity, and interfacial charge transfer in the artificial photosynthesis of CO
- 31 May 2012
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 109 (39), 15646-15650
- https://doi.org/10.1073/pnas.1119863109
Abstract
The effective design of an artificial photosynthetic system entails the optimization of several important interactions. Herein we report stopped-flow UV-visible (UV-vis) spectroscopy, X-ray crystallographic, density functional theory (DFT), and electrochemical kinetic studies of the Re(bipy-tBu)(CO)3(L) catalyst for the reduction of CO2 to CO. A remarkable selectivity for CO2 over H+ was observed by stopped-flow UV-vis spectroscopy of [Re(bipy-tBu)(CO)3]-1. The reaction with CO2 is about 25 times faster than the reaction with water or methanol at the same concentrations. X-ray crystallography and DFT studies of the doubly reduced anionic species suggest that the highest occupied molecular orbital (HOMO) has mixed metal-ligand character rather than being purely doubly occupied , which is believed to determine selectivity by favoring CO2 (σ + π) over H+ (σ only) binding. Electrocatalytic studies performed with the addition of Brönsted acids reveal a primary H/D kinetic isotope effect, indicating that transfer of protons to Re -CO2 is involved in the rate limiting step. Lastly, the effects of electrode surface modification on interfacial electron transfer between a semiconductor and catalyst were investigated and found to affect the observed current densities for catalysis more than threefold, indicating that the properties of the electrode surface need to be addressed when developing a homogeneous artificial photosynthetic system.Keywords
This publication has 26 references indexed in Scilit:
- Photoreduction of CO2 on p-type Silicon Using Re(bipy-But)(CO)3Cl: Photovoltages Exceeding 600 mV for the Selective Reduction of CO2 to COThe Journal of Physical Chemistry C, 2010
- Synthesis and Characterization of Alkali-Metal Salts of 2,2′- and 2,4′-Bipyridyl Radicals and DianionsInorganic Chemistry, 2009
- Synthesis and Photophysics of Luminescent Rhenium(I) Acetylides-Precursors for Organometallic Rigid-Rod Materials. X-ray Crystal Structures of [Re(tBu2bpy)(CO)3(tBuC.tplbond.C)] and [Re(tBu2bpy)(CO)3Cl]Organometallics, 1995
- One- and two-electron pathways in the electrocatalytic reduction of CO2by fac-Re(bpy)(CO)3Cl (bpy = 2,2′-bipyridine)Journal of the Chemical Society, Chemical Communications, 1985
- Electrocatalytic reduction of CO2 based on polypyridyl complexes of rhodium and rutheniumJournal of the Chemical Society, Chemical Communications, 1985
- Electrochemical reduction of carbon dioxide catalyzed by Rh(diphos)2ClJournal of the American Chemical Society, 1984
- Synthesis, structure, and spectroscopic properties of copper(II) compounds containing nitrogen–sulphur donor ligands; the crystal and molecular structure of aqua[1,7-bis(N-methylbenzimidazol-2′-yl)-2,6-dithiaheptane]copper(II) perchlorateJ. Chem. Soc., Dalton Trans., 1984
- Electrocatalytic reduction of carbon dioxide mediated by Re(bipy)(CO)3Cl (bipy = 2,2′-bipyridine)Journal of the Chemical Society, Chemical Communications, 1984
- Dependence of the primary isotope effect (kH/kD) on base strength for the primary amine catalyzed ionization of nitroethaneJournal of the American Chemical Society, 1970
- Potential-sweep chronoamperometry theory of kinetic currents in the case of a first order chemical reaction preceding the electron-transfer processElectrochimica Acta, 1963