Computational Comparison of Late Transition Metal (100) Surfaces for the Electrocatalytic Reduction of CO to C2 Species

Selwyn Hanselman, Marc T. M. Koper, Federico Calle-Vallejo

Index: 10.1021/acsenergylett.8b00326

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Abstract

This Letter compares the efficiency of the conversion of CO to C2 species (ethanol and ethylene) on nine late transition metal (100) surfaces (Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, Au) by means of reaction onset potentials calculated using density functional theory and atomistic thermodynamics. Due to adsorption–energy scaling relations, one can model trends in limiting potentials using only two descriptors, namely *C2O2 and *OH binding energies. The resulting activity plots (i) outline the binding properties of optimal catalysts, (ii) show little dependence of the overpotential on adsorption energies, especially on the weak-binding regime, and (iii) explain why Cu(100) reduces CO to ethylene at low overpotentials. Surprisingly, CO reduction to ethanol is predicted to be thermodynamically favorable on Ag(100). This points toward existing experimental results and calls for detailed studies of the conditions necessary to enhance CO electroreduction to ethanol using Ag and its alloys.