Electrocatalysis may form the basis for a fully renewable means to convert the greenhouse gas carbon dioxide into fuels or value-added chemicals. Since the conversion efficiency depends intimately on the mechanism of reactionâwhich is not fully understoodâab initio quantum chemical calculations may provide molecular details that allow for the rational design of electrocatalysts. This work extends the method of Goodpaster, et al.1
, which treats surfaces under applied potential and implicit solvent, to the growing string method2
for reaction path discovery. The growing string method is capable of finding the activation energy and reaction energy from a starting reactant and a set of driving coordinates for bond breaking or forming. Several vital surface reactions are conducted to demonstrate the efficacy of this method for CO2 reduction under potential bias on a Cu(100) surface. Furthermore, the same reaction is investigated on a Ag(100) surface to explain the experimentally observed behavior of silver to switch between carbon monoxide or hydrogen production as a function of potential bias. The reactions path discovery examples on Cu and Ag will demonstrate the power of the growing string method for investigating surface reactions under electrochemical bias, and provide foundational insights into the rational design of electrocatalysts.
 Goodpaster, J. D.; Bell, A. T.; Head-Gordon, M. Identification of Possible Pathways for C-C Bond Formation during Electrochemical Reduction of CO2: New Theoretical Insights from an Improved Electrochemical Model. Phys. Chem. Lett. 7 (2016) 1471-1477.
 Jafari, M.; Zimmerman, P. M. Reliable and Efficient Reaction Path and Transition State Finding for Surface Reactions with the Growing String Method. J. Comput. Chem. 38 (2017) 645-658.