Constructing porous RuCu nanotubes with highly efficient alloy phase for water splitting in different pH conditions

Abstract

Controlling surface composition is a direct approach to develop active electrocatalysts for water splitting. Here, porous RuCu nanotubes with Ru1Cu1 alloy phase are successfully constructed by a multi-step wet chemistry method, which illustrate excellent performance for water splitting in different pH conditions. Particularly, it only requires 11 and 229 mV to get 10 mA cm−2 for hydrogen evolution reaction and oxygen evolution reaction in 1 M KOH medium, respectively. Moreover, it just requires nearly 2.0 V to reach 300 mA cm−2 in flowing alkaline water electrolyzer device, which is much better than Pt/C // RuO2 system. Further mechanism studies reveal that Ru1Cu1 alloy phase acts as the main role in hydrogen evolution because it largely weakens the free energy of adsorption hydrogen and activates water molecules to facilitate the dissociation. Afterwards, Ru1Cu1 alloy also effectively reduces the free energy of rate-determining step during oxygen evolution reaction. Besides, the unique one dimensional and porous structure of nanotubes strengthens the transfer of electrons and the releasing of gas products, enhancing the reaction kinetics. This work emphasizes the importance of alloy composition for water splitting, which guides the rational regulation of electrocatalysts.