Accelerated Discovery of Stable and Active Materials for Oxygen Electrocatalysis

A transition from a society based on fossil fuels to a CO₂–neutral sustainable energy resources is critical to address the global climate crisis and increasing energy demands. One aspect of this grand challenge involves sustainable energy storage and conversion technologies. Solar and electrical energy can be stored in chemical bonds by splitting water to produce hydrogen. Hydrogen can then be oxidized to generate energy when coupled with oxygen reduction. However, the energy efficiencies of these renewable technologies have been hampered by the sluggish kinetics of oxygen-based (oxygen evolution reaction-OER and oxygen reduction reaction-ORR) electrochemical reactions and consequently demand a high overpotential to drive these reactions, even when using state–of–the–art oxygen electrocatalysts.[1] Moreover, the stability of these materials should be on par with its catalytic activity to develop electrocatalysts for practical applications.[2]

In this work, we use computational Pourbaix diagram to identify acid stable non–binary oxide materials by analyzing the aqueous stability of oxides in the Materials Project database[3] at pH = 0 under typical potential ranges of 0.6 – 1.0 V (vs. SHE) and 1.2 – 2.0 V (vs. SHE) for ORR and OER, respectively. Then we performed a systematic high-throughput screening of the ORR and OER activity of these stable materials by determining unique surface terminations and active sites, incorporating surface coverages of the reaction intermediates under reaction conditions, and calculating adsorption free energies of reaction intermediates to predict theoretical ORR limiting potentials and OER overpotentials. Promising candidates were then experimentally synthesized, characterized, and tested for their activity, stability, and selectivity. Finally, on the basis of theoretical and experimental findings, rational catalyst design principles for next-generation oxygen electrocatalysts are established.

References:

[1] Z.W. Seh, J. Kibsgaard, C.F. Dickens, I. Chorkendorff, J.K. Nørskov, T.F. Jaramillo, Combining theory and experiment in electrocatalysis: Insights into materials design, Science 355 (2017) eaad4998

[2] J. Kibsgaard, I. Chorkendorff, Considerations for the scaling-up of water splitting catalysts, Nat. Energy. 4 (2019) 430–433

[3] A. Jain, S.P. Ong, G. Hautier, W. Chen, W.D. Richards, S. Dacek, S. Cholia, D. Gunter, D. Skinner, G. Ceder, K.A. Persson, Commentary: The materials project: A materials genome approach to accelerating materials innovation, APL Mater. 1 (2013) 011002