A co-axial structure composed of RuO2 on defective N-doped carbon nanotubes as a highly efficient electrocatalyst for overall water splitting

The rational development of catalysts with high efficiency and stability for facilitating the hydrogen evolution reaction and the oxygen evolution reaction (HER/OER) is of immense importance in the process of overall water splitting (OWS). Herein, the synthesis of a co-axial structure composed of RuO2 on defective N-doped carbon nanotubes (RuO2-DNCTs) via a facile self-template strategy is reported. Due to their hollow co-axial interior structure which increases their catalytic activity and conductive capacity, RuO2-DNCTs exhibit remarkable HER and OER performance. In particular, the mass activity of RuO2-DNCTs for HER is 3.9 times superior to that of commercially available Pt/C. A bi-functional RuO2-DNCT-based alkaline electrolyzer is developed for overall water splitting (OWS), exhibiting remarkable durability and a low cell potential of merely 1.48 V for achieving 10 mA cm(2). Density functional theory (DFT) suggested that the optimization of the adsorption energy for Ru sites during the OER process can be achieved by transferring electrons from defective nitrogen-doped carbon (DNC) to RuO2, leading to a reduction in the reaction barrier and enhancement in reaction kinetics.