Metastable five-fold twinned Ru incorporated Cu nanosheets with Pt-like hydrogen evolution kinetics

Abstract Precisely tuning the geometric and phase structure of noble metal-based heterostructure nanomaterials has been an effective way to induce a metastable defect interface system for the fast hydrogen evolution reaction (HER) kinetics in alkaline media. However, the unstable defect nature of metastable materials hinders their practical applications. Herein, as demonstrated by the theoretical calculation, the optimal Gibbs free energy of adsorbed H2O (ΔGH2O) and water dissociation (ΔGB) can be created for five-fold twinned Ru on Cu NSs with metastable interfaces. Thus, we successfully design and construct an in-situ metastable interface in five-fold twinned Ru supported on vertically oriented Cu nanosheets (Cu NSs) (devoted as CuRux NSs). Among them, CuRu8 NSs display unprecedented overpotentials of 8 and 39 mV at 10 and 100 mA cm−2, respectively. Furthermore, CuRu8 NSs also demonstrate high intrinsic mass activity of 77.528 A g−1 at an overpotential of 20 mV and a large exchange current density of 5.014 mA cm−2, with outstanding stability (almost no activity degradation for 130 h). These represent one of the best alkaline HER catalysts to date for Ru-based catalysts. Importantly, CuRu8 NSs possess nearly 100% Faradaic yield, confirming the high selectivity toward hydrogen evolution reaction. Furthermore, the fine structural analysis evidences that the in-situ incorporated five-fold twinned Ru nanoparticles coupled electronically with Cu NSs not only avoid migration and aggregation of the metal particles, but also effectively promote the formation of heterostructure nanosheet arrays with abundant active sites, enhancing the alkaline hydrogen evolution kinetics.