MOF-derived RuCoP nanoparticles-embedded nitrogen-doped polyhedron carbon composite for enhanced water splitting in alkaline media.

The RuCoP@CN electrocatalyst acts as an OER/HER bifunctional catalyst for overall water splitting in alkaline media, which is superior to the reported RuO 2 and Pt/C couple electrode. [Display omitted] • RuCoP were embedded in nitrogen-doped polyhedron shape carbon which presents rhombus faces and straight edges. • RuCoP@CN show excellent activity for both hydrogen evolution reaction and oxygen evolution reaction in alkaline media. • RuCoP@CN || RuCoP@CN for overall water splitting, which is superior to the reported RuO 2 and Pt/C couple electrode. • The superior water splitting activity of RuCoP@CN is systematically revealed by DFT calculations. Water splitting is considered as a promising candidate for renewable and sustainable energy systems, while developing efficient, inexpensive and robust bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) still remains a challenge. Herein, the well-designed RuCoP nanoparticles embedded in nitrogen-doped polyhedron carbon (RuCoP@CN) composite is fabricated by in-situ carbonization of Co based zeolitic imidazolate framework (ZIF-67) and phosphorization. Ru-substituted phosphate is proved to be imperative for the electrochemical activity and stability of individual catalysts, which can efficiently yield the active electronic states and promote the intrinsic OER and HER activity. As a result, a current density of 10 mA cm−2 is achieved at a cell voltage as low as 1.60 V when the RuCoP@CN electrocatalyst applied for the overall water splitting, which is superior to the reported RuO 2 and Pt/C couple electrode (1.64 V). The density functional theory (DFT) calculations reveal that the introduction of Ru and P atoms increase the electronic states of Co d-orbital near the Fermi level, decreasing the free energy of the hydrogen adsorption and H 2 O dissociation for HER and the rate-limiting step for OER in alkaline media. [ABSTRACT FROM AUTHOR]