Tuning the electronic communication of the Ru–O bond in ultrafine Ru nanoparticles to boost the alkaline electrocatalytic hydrogen production activity at large current density

Abstract

The rational design and synthesis of efficient electrocatalysts for the hydrogen evolution reaction (HER) are of great importance for alkaline hydrogen production. This study describes a nanocomposite material design, in which ultrafine and small (2.0–3.5 nm) Ru nanoparticles coordinated with O atom sites are supported on a carbon matrix formed by C₆₀(OH)_n (Ru–O/C-600). The Ru–O bonds create a channel of electron communication to facilitate charge transfer and improve the conductivity of electrocatalysts. The ultrafine and evenly-distributed Ru nanoparticles provide a high density of active sites to extend electrochemical surface areas. Ru–O/C-600 achieved a low overpotential of 32 mV at a current density of 10 mA cm⁻² with a small Tafel slope of 51.8 mV dec⁻¹ and long-term stability of 50 h. Moreover, Ru–O/C-600 also gave an output of 500 and 1000 mA cm⁻² with an overpotential of 242 and 383 mV for practical use. These findings open up new avenues for developing Ru-based hybridization materials with enhanced electron transfer and abundant active sites for HER performance.