Electronic Structure-Dependent Water-Dissociation Pathways of Ruthenium-Based Catalysts in Alkaline H2-Evolution

Ruthenium (Ru)-based catalysts have displayed compelling hydrogen evolution activities, which hold the promising potential to substitute platinum in alkaline H-2-evolution. In the challenging alkaline electrolytes, the water-dissociation process involves multistep reactions, while the profound origin and intrinsic factors of diverse Ru species on water-dissociation pathways and reaction principles remain ambiguous. Here the fundamental origin of water-dissociation pathways of Ru-based catalysts in alkaline media to be from their unique electronic structures in complex coordination environments are disclosed. These theoretical results validate that the modulated electronic structures with delocalization-localization coexistence at their boundaries between the Ru nanocluster and single-atom site have a profound influence on water-dissociation pathways, which push H2O* migration and binding orientation during the splitting process, thus enhancing the dissociation kinetics. By creating Ru catalysts with well-defined nanocluster, single-atom site, and also complex site, the electrocatalytic data shows that both the nanocluster and single-atom play essential roles in water-dissociation, while the complex site possesses synergistically enhanced roles in alkaline electrolytes. This study discloses a new electronic structure-dependent water-dissociation pathway and reaction principle in Ru-based catalysts, thus offering new inspiration to design efficient and durable catalysts for the practical production of H-2 in alkaline electrolytes.

Automated summary

This study reveals the fundamental origin of water-dissociation pathways of Ru-based catalysts in alkaline media and demonstrates the profound influence of their electronic structures. The results show that modulated electronic structures at the boundaries between the Ru nanocluster and single-atom site enhance the dissociation kinetics. By understanding this electronic structure-dependent pathway, new catalysts for the production of H-2 in alkaline electrolytes can be designed.