Synergistic Mechanism of Sub-Nanometric Ru Clusters Anchored on Tungsten Oxide Nanowires for High-Efficient Bifunctional Hydrogen Electrocatalysis

The construction of strong interactions and synergistic effects between small metal clusters and supports offers a great opportunity to achieve high-performance and cost-effective heterogeneous catalysis, however, studies on its applications in electrocatalysis are still insufficient. Herein, it is reported that W18O49 nanowires supported sub-nanometric Ru clusters (denoted as Ru SNC/W18O49 NWs) constitute an efficient bifunctional electrocatalyst for hydrogen evolution/oxidation reactions (HER and HOR) under acidic condition. Microstructural analyses, X-ray absorption spectroscopy, and density functional theory (DFT) calculations reveal that the Ru SNCs with an average Ru-Ru coordination number of 4.9 are anchored to the W18O49 NWs via Ru-O-W bonds at the interface. The strong metal-support interaction leads to the electron-deficient state of Ru SNCs, which enables a modulated Ru-H strength. Furthermore, the unique proton transport capability of the W18O49 also provides a potential migration channel for the reaction intermediates. These components collectively enable the remarkable performance of Ru SNC/W18O49 NWs for hydrogen electrocatalysis with 2.5 times of exchange current density than that of carbon-supported Ru nanoparticles, and even rival the state-of-the-art Pt catalyst. This work provides a new prospect for the development of supported sub-nanometric metal clusters for efficient electrocatalysis.

Automated summary

The construction of strong interactions and synergistic effects between small metal clusters and supports provides an opportunity for high-performance and cost-effective heterogeneous catalysis. In this study, sub-nanometric Ru clusters supported on W18O49 nanowires were found to be an efficient bifunctional electrocatalyst for hydrogen evolution/oxidation reactions under acidic condition. This work offers a new prospect for the development of supported sub-nanometric metal clusters for efficient electrocatalysis.