Mechanisms of CO2 Reduction on Metal and Modified Semiconductor Electrodes.
Abstract
The goal of this project is to elucidate the mechanism of the electrochemical reduction of CO2 to methanol. A number of materials have been identified that form methanol in an electrochemical cell. These are GaAs, InP, Mo, W, and Ru. These electrode materials are used to determine the reaction mechanism. It has been shown that chemical steps limit the rate of CO2 reduction on GaAs, and therefore, the extent of surface chemical reactions and their role in the formation of methanol are of great interest. We are using a two-fold approach to mechanistic determination. First, elementary steps in the mechanism are postulated and then the thermodynamics of these steps is evaluated. The calculations allow uss to: 1) reject steps with unfavorable energetics, 2) aid in the calculation of rates of feasible steps, and 3) obtain a global view of the probability of certain steps on a wide variety of materials. The experimental phase of this study includes electrochemical kinetic measurements on the CO2 reduction reaction. Essential data to be acquired include rates of product formation and faradaic efficiencies as a function of electrode potential, and pH. In addition, we are attemptind to observe surface-bound reaction intermediates. Computer data aquisiton and manipulation of fast voltage transient data and FTIR are being employed. Identification of intermediates will suggest a rate limiting step and the results will be compared with model calculations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 21, 1986
- Accession Number
- ADA173695
Entities
People
- D. P. Summers
- K. W. Frese Jr.
Organizations
- SRI International