High-index faceted RuCo nanoscrews for water electrosplitting

Abstract

Shape control has realized huge success for developing efficient Pd/Pt-based nanocatalysts, but the control of Ru-based nanocrystals remains a formidable challenge due to the inherent anisotropy in hexagonal closed-packed nanocrystals. Herein, a class of unique RuCo nanoscrews (NSs) for water electrosplitting is successfully synthesized with rough surfaces and the exposure of steps and edges. Those high-index faceted RuCo NSs show superior performance for overall water electrosplitting, where a low cell voltage of 1.524 V (@ 10 mA cm−2) and excellent stability for more than 20 h (@ 10 mA cm−2) for overall water electrosplitting in 1 m KOH is achieved. The enhanced performance of RuCo NSs is due to the optimization of the binding energy with the intermediate species and the reduced energy barrier of water dissociation. Density functional theory calculations reveal that the RuCo NS structure intrinsically endows various ridges and edges, which create low coordinated Ru- and Co-sites. These active Ru- and Co-sites present high efficiencies in electronic exchange and transfer between adsorbing O species and nearby lattice sites, guaranteeing the high H2O-splitting activities. This present work opens up a new strategy for creating high-performance electrocatalysts for water splitting.