Inducing electronic asymmetricity on Ru clusters to boost key reaction steps in basic hydrogen evolution

Modulating electronic asymmetricity of catalysts is a novel option to regulate the electrocatalytic performance. Nevertheless, the efficient regulation of asymmetric degree of heterostructured catalysts at the atomic level still remains challenging. Herein, Ru nanoclusters (NCs, average particle size of similar to 1.3 nm) were anchored on carbon materials doped by controllable N functional groups to optimize the electronic asymmetricity toward efficient hydrogen evolution reaction (HER). The electronic interaction between Ru and N species, and hence, the asymmetric electronic distribution of Ru NCs is subjectively manipulated by precisely tailoring the type of N dopants, especially pyrrolic-N, of carbon substrates. As a result, the pyrrolic-N dominated Ru-based heterostructures exhibit excellent HER activity compared to most of the current Ru-based electrocatalysts in basic media. Multiple spectroscopy experiments and density functional theory simulations demonstrate that the asymmetric distribution of surface electron of Ru-based heterostructures not only accelerates H2O adsorption and dissociation at interfacial Ru sites with positive charge but also facilitates the adsorption behavior of hydrogen on surface Ru sites with negative charge, thereby simultaneously optimizing the elementary steps in basic HER process. The present findings would provide some crucial understanding in manipulating the local electronic asymmetricity toward reasonable design and fabrication of advanced catalysts and beyond.

Automated summary

Modulating the electronic asymmetricity of catalysts is a new approach to improve electrocatalytic performance, but controlling the degree of asymmetry in heterostructured catalysts at the atomic level is still challenging. In this study, Ru nanoclusters were anchored on carbon materials doped with controllable N functional groups to optimize the electronic asymmetricity for efficient hydrogen evolution reaction (HER). By tailoring the type of N dopants, particularly pyrrolic-N, the electronic interaction between Ru and N species was manipulated, resulting in Ru-based heterostructures with excellent HER activity in basic media. Spectroscopy experiments and simulations confirmed that the asymmetric distribution of surface electrons in Ru-based heterostructures enhanced H2O adsorption and dissociation at positively charged interfacial Ru sites, and promoted hydrogen adsorption at negatively charged surface Ru sites, optimizing the elementary steps in the basic HER process. These findings provide crucial insights for the design and fabrication of advanced catalysts.