Toward a Fundamental Understanding of Strain Generation and Strain Tuning for the Fuel Cell Applications

The development of industrial electrocatalysts with excellent performance in fuel cells strongly relies on the fundamental understanding of governing principles of catalysis from fundamental research on well-defined model systems. One particularly successful strategy has been to tune surface strain and thereby modulate the surface electronic structure and energetics of reaction intermediates, leading to a fundamental understanding and identification of catalysts with improved activity. For the well-known example of the oxygen reduction reaction (ORR) on platinum in fuel cells, previous studies indicated that a 1% compressive strain could improve the activity by more than 300%. While the concept of tailoring the reactivity of metal catalysts through surface strain has been discussed over two decades, fundamental challenges remain regarding both strain generation and strain tuning. In the present contribution, We will share our recent progress on these topics, including [1] tunable intrinsic strain in two-dimensional transition metal electrocatalysts, [2] tunable intrinsic strain in stepped transition metal electrocatalysts, and [3] strain tuning of supported transition metal overlayers. We will demonstrate [1] how these fundamental understanding can be used to understand terrace-width dependent ORR activity of stepped Pt surfaces that have puzzled the community over a decade; and [2] how they pave the way toward developing both model electrocatalysts and industrial electrocatalysts with significantly improved performance toward the oxygen reduction reaction. References Wang, Z. Zeng*†, W. Gao, T. Maxson, D. Raciti, M. Giroux, X. Pan, C. Wang, J. Greeley,. Science 2019, 363, 870-874. Wang, W. Gao, Z. Liu, Z. Zeng, Y. Liu, M. Giroux, M. Chi, G. Wang, J. Greeley, X. Pan, C. Wang, ACS Catal. 2018, 8, 35-42. J. Steinbach, C. Duru, A. T. Haug, A. E. Hester, M. Kuznia, K. A. Lewinski, S. M. Luopa, J. T. Petrin, G. M. Thoma, A. J. Kropf, D. J. Myers, D. Yang, D. A. Cullen, J. Greeley, Z. Zeng, ECS Transactions 2017, 80, 659-676. Zeng, J. Greeley, Nano Energy 2016, 29, 369.