Stabilizing Electron-Deficient Ru Nanoclusters via Strong Electronic Metal-Support Interaction for Practical Anion-Exchange Membrane Electrolyzer

Ruthenium (Ru)-based hydrogen evolution reaction (HER) electrocatalysts are promising candidates for assembling high-performance anion exchange membrane water electrolyzer (AEMWE) while their intrinsic activities are restricted due to the strong Ru & horbar;H bond strength. Herein, we present the synthesis and stabilization of electron-deficient Ru nanoclusters on oxygen-functionalized carbon nanotube (Ru/O-CNT) via strong electronic metal-support interaction (EMSI) toward highly efficient and stable alkaline HER. A scalable high-temperature shock method is used to anchor Ru nanoclusters on O-CNT, which suppresses the aggregation of Ru clusters and the loss of O anion during synthesis, thus strengthening the EMSI between the two components via Ru-O-C link. The strong EMSI helps to stabilize Ru at electron-deficient state at reductive potentials and optimizes the Ru & horbar;H bond strength. Consequently, Ru/O-CNT delivers outstanding performances for alkaline HER with a small overpotential of 10 mV at 10 mA cm-2, which is superior to the benchmark Pt/C and most reported Ru-based electrocatalysts. More impressively, an AEMWE assembled with Ru/O-CNT as cathode achieves high current densities of 1 and 5 A cm-2 at low cell voltages of 1.68 and 2.09 V, respectively, at a Ru mass loading of only 20 mu g cm-2.