Correlating Single-Atomic Ruthenium Interdistance with Long-Range Interaction Boosts Hydrogen Evolution Reaction Kinetics

Correlated single-atom catalysts (c-SACs) with tailored intersite metal-metal interactions are superior to conventional catalysts with isolated metal sites. However, precise quantification of the single-atomic interdistance (SAD) in c-SACs is not yet achieved, which is essential for a crucial understanding and remarkable improvement of the correlated metal-site-governed catalytic reaction kinetics. Here, three Ru c-SACs are fabricated with precise SAD using a planar organometallic molecular design and pi-pi molecule-carbon nanotube confinement. This strategy results in graded SAD from 2.4 to 9.3 angstrom in the Ru c-SACs, wherein tailoring the Ru SAD into 7.0 angstrom generates an exceptionally high turnover frequency of 17.92 H2 s-1 and a remarkable mass activity of 100.4 A mg-1 under 50 and 100 mV overpotentials, respectively, which is superior to all the Ru-based catalysts reported previously. Furthermore, density functional theory calculations confirm that Ru SAD has a negative correlation with its d-band center owing to the long-range interactions induced by distinct local atomic geometries, resulting in an appropriate electrostatic potential and the highest catalytic activity on c-SACs with 7.0 angstrom Ru SAD. The present study promises an attractive methodology for experimentally quantifying the metal SAD to provide valuable insights into the catalytic mechanism of c-SACs. Ru-based correlated single-atom catalysts (c-SACs) with different and precise single-atomic interdistances are constructed via a combination of planar organometallic molecular design and pi-pi molecule-carbon nanotube confinement, for systematic investigation of the structure-activity relationship at the atomic level, precisely manipulating the electrostatic force using the atomic structure and leading to severalfold enhancement in the activity of c-SACs with multimetal sites.image