The continuous increase in the population and industrial development has led to an increase in global energy demand. Most of the current primary energy consumption is obtained from the burning of fossil fuels that releases an enormous amount of greenhouse gases. Notably, hydrogen (H₂) is a clean and eco-friendly fuel and has already shown its ability to be a promising substitute for fossil energy. One of the cleanest ways to produce H₂ is by splitting of water by electrolysis.¹ Recently, numerous inexpensive and robust catalysts based on transition metals (oxides, chalcogenides, pnictides, carbides, or alloys, etc.) have been developed for water splitting with reasonable activity.² Despite the massive development of electrocatalysts for water splitting, huge challenges still exist for their use in practical application. Our current goals are to uncover new classes of suitable unconventional catalysts based on non-noble metals that can offer better overall catalytic efficiency for practical applications; to study their structural transformation, active sites, surface, and bulk structures; and to investigate the influence of precatalysts on the properties of the final catalyst.

In this context, intermetallic compounds have numerous advantages owing to their intriguing structural, chemical and physical properties, especially being catalytically active and electrically conductive at the same time and thus, making them an ideal class of materials for electrocatalytic applications.³ Using different approaches, we synthesized various classes of intermetallic materials (e.g., stannides, gallides, germanides, indates, silicides, etc.) with interesting structural and electronic features.^4-5 Most of these materials exhibited remarkable electrocatalytic activity for water splitting, yielding considerably low overpotentials with enhanced long-term durability for both O₂ and H₂ generation in alkaline media. The active catalyst structure during each half-reaction (H₂ and O₂) and the correlation of the structure with the activity of the catalysts were revealed by a profound understanding of the system using in-situ and ex-situ techniques. This talk will provide a brief summary of the ongoing water splitting research as well as delve into selected examples of our recent work to pave the way to a concept-guided design system beyond water electrolysis (e.g., paired electrolysis).

References

[1] H Yang, M Driess, P. W. Menezes, Adv. Energy Mater. 2021, 11, 2102074.

[2] Z Chen, H Yang, Z Kang, M Driess, P. W. Menezes, Adv. Mater. 2022, 2108432.

[3] C. Walter, P. W. Menezes, M. Driess, Chem. Sci. 2021, 12, 8603.

[4] N. Hausmann, R. Beltrán-Suito, S. Mebs, V. Hlukhyy, T. F. Fässler, H. Dau, M. Driess, P. W. Menezes, Adv. Mater. 2021, 33, 2008823.

[5] B. Chakraborty, R. Beltrán-Suito, S. Garai, J. N. Hausmann, M. Driess, P. W. Menezes, Adv. Energy Mater. 2020, 10, 2001377.