(561c) Oxides Supported Transition Metal Single Atoms for Oxygen Electrocatalysis

Achieving a sustainable energy future is critical to overcoming the ever-increasing energy demands, reducing our dependence on conventional energy sources based on fossil fuels, and impeding climate change. One aspect of this grand challenge involves developing sustainable energy storage and conversion technologies to convert electricity into fuels and chemicals, as renewable energy sources (solar, wind, and hydroelectric) are intermittent. The oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) play a critical role in such technologies; however, the energy efficiencies have been hampered by the sluggish kinetics of OER and ORR.¹ To date, the best–known catalysts in acidic solution for OER are IrO₂ and RuO₂ and for ORR are Pt-based materials. However, these catalysts have overpotentials of ~ 0.3 V, and most importantly, the high cost and scarcity of IrO₂, RuO₂, and Pt and the limited stability under high oxidative potentials hinder their commercial viability. Recently, single-atom catalysts (SACs) supported on acid-stable oxides have emerged as an important class of electrocatalysts due to the prospects of maximizing the efficiency of precious metal utilization, developing well-defined single-site materials, and as a potential strategy to break the scaling relations.²

In this work, we selected SnO₂ as an acid-stable oxide host material and considered 29 elements corresponding to 3d, 4d, and 5d transition metals as SACs. First, we systematically analyzed the thermodynamic and aqueous stability and activity of these SACs. Then, we performed a high-throughput screening³ of the ORR and OER activity to identify the most promising SAC candidates for experimental validation. Based on these theoretical findings, rational catalyst design principles for next-generation SACs based oxygen electrocatalysts are established.

1 Seh, Z. W. et al. Science 355, eaad4998 (2017)

2 Chen, Y. et al. Joule 2, 1242–1264 (2018)

3 Gunasooriya, G. T. K. K. et al. ACS Energy Lett. 5, 3778–3787 (2020)