Facet-Junction Induced Strong Metal Support Interaction for Enhanced Alkaline Hydrogen Evolution Reaction

Strong metal-support interaction (SMSI) plays a critical role in enhancing the catalytic performance of electrocatalysts. Currently, effective approaches to enhance the SMSI effect in supported electrocatalysts still need to be developed, and a comprehensive atomic-level understanding of the underlying reaction mechanisms remains unclear. In this study, a novel facet-junction strategy is proposed to enhance the SMSI between the loaded Ru atoms and the Co 3 O 4 support. By modulating the ratio of exposed facet for (111)/(100) crystal plane in Co 3 O 4 , the hydrogen evolution reaction (HER) performance can be dramatically enhanced by 560% and can achieve a Pt-like HER activity with the overpotential of 45 mV. Detailed analysis with atomic-resolution integrated differential phase contrast (iDPC)-scanning transmission electron microscopy (STEM), atomic-resolution high angle annular dark field (HADDF)-STEM, and electron energy loss spectroscopy (EELS) further proved that with proper (111)/(100) crystal plane ratio, the intensified charge distribution near the facet-junction region would modify the electronic structure around the active sites. This work provides new insights to enhance the SMSI and will contribute to the rational design of highly efficient electrocatalysts for water splitting.