A Sustainable Route to Ruthenium Phosphide (RuP)/Ru Heterostructures with Electron-Shuttling of Interfacial Ru for Efficient Hydrogen Evolution

Ruthenium (Ru) is a promising electrocatalyst for the hydrogen evolution reaction (HER), despite suffering from low activity in non-acidic conditions due to the high kinetic energy barrier of H2O dissociation. Herein, the synthesis of carbon nanosheet-supported RuP/Ru heterostructures (RuP/Ru@CNS) from a natural polysaccharide is reported and demonstrates its behavior as an effective HER electrocatalyst in non-acidic conditions. The RuP/Ru@CNS exhibits low overpotential (106 mV at 200 mA center dot cm-2) in alkaline electrolyte, exceeding most reported Ru-based electrocatalysts. The electron shuttling between Ru atoms at the RuP/Ru interface results in a lowered energy barrier for H2O dissociation by electron-deficient Ru atoms in the pure Ru phase, as well as optimized H* adsorption of electron-gaining Ru atoms in the neighboring RuP. A low H* spillover energy barrier between Ru atoms at the RuP/Ru interface further boosts HER kinetics. This study demonstrates a sustainable method for the fabrication of efficient Ru-based electrocatalysts and provides a more detailed understanding of interface effects in HER catalysis. In the RuP/Ru heterostructure, the electron-deficient Ru atom in the Ru phase is better able to adsorb and dissociate H2O to form H*, whereas the electron-gaining Ru in RuP provides optimized H* adsorption to generate H2. The low H* spillover energy barrier between Ru atoms across the RuP/Ru interface facilitates hydrogen transfer from one side of the interface to the other, resulting in efficient non-acidic HER kinetics. image