Electrochemical Reduction of CO2 Using Group VII Metal Catalysts

Extensive spectroscopic studies of molecular electrocatalysts have enabled several design approaches for the creation of new functional electrolysis systems for carbon dioxide reduction. Reaction pathways can be manipulated by controlling a number of factors affecting the chemical environment through careful selection of Lewis or Brønsted acids or synthetic modification that controls metal–metal interactions, including noncovalent interactions like hydrogen bonding. IR spectroelectrochemistry has proved to be a valuable tool for observing chemical characteristics of electrocatalysts at catalytically relevant potentials and understanding the intermediates between the catalyst precursor and active catalyst states. Anthropogenic CO2 emissions, primarily from the combustion of fossil fuels, are driving climate change at an alarming rate. Our current dependence on carbon-based fuels has motivated research interest in the capture and catalytic reduction of carbon dioxide back to liquid fuels. Electrochemical reduction of carbon dioxide has been intensely researched over the past decade. Here, some of the important contributions made to this field over the past decade using the Group VII transition metal bipyridine catalysts are reviewed. Strategies to further our mechanistic understanding of the electrocatalytic reduction of CO2 to CO are described. Anthropogenic CO2 emissions, primarily from the combustion of fossil fuels, are driving climate change at an alarming rate. Our current dependence on carbon-based fuels has motivated research interest in the capture and catalytic reduction of carbon dioxide back to liquid fuels. Electrochemical reduction of carbon dioxide has been intensely researched over the past decade. Here, some of the important contributions made to this field over the past decade using the Group VII transition metal bipyridine catalysts are reviewed. Strategies to further our mechanistic understanding of the electrocatalytic reduction of CO2 to CO are described. a typical experiment uses a reference electrode (a standard potential), a working electrode (where the potential is applied), and a counter electrode (closes the current circuit). This electrochemical technique measures the current in the electrochemical cell as a function of the applied potential at the working electrode. refers to the atomic orbital that occupies the z-axis of an metal atom. a molecule that can change and increase the rate of an electrochemical reaction without being consumed in the reaction. a chemical reaction involving the transfer of electrons from the electrode to the surface. the percentage of the charge transferred in a system that facilitates a specific reaction. a linear free-energy relationship for modeling the electronic effect of substituents on aromatic systems. IR spectroscopy of a specially designed electrochemical cell, which provides qualitative and quantitative information on the processes occurring under applied potential. the potential difference between the standard potential and the potential where the redox event is observed, or the ‘extra’ potential needed to drive a redox reaction. a fuel synthesized from small ubiquitous molecules (i.e., water, carbon dioxide, nitrogen) using solar energy. a technique for observing chemical reaction kinetics on the millisecond timescale. a nonlinear spectroscopic technique used to analyze surfaces. This typically involves two laser incident sources, which generate an output that is the sum of the two incident light sources. a plot of the Tafel equation, which relates the rate of an electrochemical reaction to the overpotential applied to achieve that rate. a measure of the rate of a catalyst and calculated as the number of chemical conversions of a substrate per second facilitated by the catalyst. This is related to the TON, which is the maximum number of chemical conversions the catalyst will perform of the desired chemical conversion.