(17b) Mechanistic Studies of the Electrochemical Reduction of CO2 on Gold Conference: AIChE Annual MeetingYear: 2015Proceeding: 2015 AIChE Annual MeetingGroup: Catalysis and Reaction Engineering DivisionSession: Electrocatalysis and Photoelectrocatalysis I: CO2 Reduction Time: Sunday, November 8, 2015 - 3:50pm-4:10pm Authors: Dunwell, M., University of Delaware Lu, Q., Columbia University Xu, B., University of Delaware Jiao, F., University of Delaware Yan, Y., University of Delaware Chen, J. G., Columbia University The lack of mechanistic understanding of electrode mediated CO2 electrochemical reduction is a severe barrier in development of active and selective electrocatalysts for CO2 reduction. Au is an ideal material for initial mechanistic studies due to its high selectivity toward a single product (CO). Vibrational spectroscopy, electrokinetic studies, isotopic labeling, and mass spectroscopy were combined in the mechanistic study of CO2 reduction on Au electrodes. We demonstrate for the first time that pH near the electrode surface is significantly elevated relative to the bulk. In addition, we propose that adsorption of metal cations at sufficiently low potentials could be a key factor in limiting the transport of reactants to the electrode surface, thus suppressing the reaction rate.