Electrocatalysts with Increased Activity for Coelectrolysis of Steam and Carbon Dioxide in Solid Oxide Electrolyzer Cells

Abstract

The high-temperature coelectrolysis system can be helpful to solve environmental issues by reducing carbon dioxide emissions. The technology is highly promising because of its high selectivity and conversion efficiency toward the products. In addition, the produced syngas can also be further converted into very useful synthetic fuels. In this study, we investigated the series of reactions on a wide range of transition metals to evaluate their ability to increase the activity of the conventional Ni catalysts used in the fuel electrode of solid oxide electrolyzer cells. We theoretically identified that the adsorption energies of O and H are the common descriptors of coelectrolysis of steam and carbon dioxide. We then combined microkinetic analysis with density functional theory calculations to derive a volcano plot to predict the activity of coelectrolysis on a variety of transition metals. We could successfully suggest good candidates of Ni-based bimetallic alloy catalysts with excellent activities in the coelectrolysis. Our result will provide insight into improving the electrode catalysts used in the high-temperature coelectrolysis system.