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A facile construction of Ru/RuO 2 composite with porous reticular structure (denoted as Ru/RuO 2 -PRS) by controllable pyrolysis of Ru3+ coordinated cyanoguanidine was presented for oxygen evolution reaction (OER). The Ru/RuO 2 heterostructure was identified in Ru/RuO 2 -PRS. Taking the advantages of the Ru/RuO 2 heterostructure and large specific surface area, Ru/RuO 2 -PRS exhibits much more improved OER activity with much lower onset potential and overpotential to reach the current density of 10 mA cm−2 compared with RuO 2 porous powder and RuO 2 nano-particles counterparts in both acidic and alkaline solution. Specifically, Ru/RuO 2 -PRS exhibits much improved durability because the unique Ru/RuO 2 heterostructure relieves the dissolution of RuO 2 at high anodic potential that has been the bottleneck of Ru-based catalysts for OER, especially in acidic electrolyte. This study provides a new strategy to promote the OER application in acidic solution. • We present a facile one-step calcination method to synthesize 3D porous reticular structure of Ru/RuO 2 (Ru/RuO 2 -PRS). • The as prepared Ru/RuO 2 -PRS presents abundant Ru/RuO 2 heterostructure, which benefits to the electrocatalytic process. • Ru/RuO 2 -PRS exhibits excellent OER activity and stability in both acid and alkaline electrolyte. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have considered as excellent electrocatalysts with high reactivity for hydrogen evolution reaction (HER). While electro-catalytic properties of TMPs are restricted by uneven dispersion, small surface area, poor conductivity, and unsatisfied stability. Herein, a facile procedure was proposed to prepare a hierarchical structure of FeCoP nanoparticles anchored on N-doped carbon/multi-walled carbon nanotubes (NC/CNT) nanocomposites. With the increased porosity and conductive network of NC/CNT substrate, the as-synthesized NC/CNT-FeCoP provided abundant active sites for HER. Meanwhile, due to the synergistic effect between the dual metal centers and uniform distribution of bimetallic composites, the synthesized electrocatalyst can provide enhanced intrinsic activity. Therefore, the optimized NC/CNT-FeCoP delivered excellent HER activity in 1.0 M KOH and 0.5 M H 2 SO 4 with overpotentials of 182 mV and 150 mV at 10 mA cm−2, respectively. Moreover, NC/CNT-FeCoP coupled two-electrode system needs a low cell potential of 1.68 V at 10 mA cm−2 for overall water splitting. First-principle calculations indicated that N-doped graphene substrate can adjust the electronic properties of surface metal site and consequently affect the H adsorption strength to yield an improved HER activity. Our work demonstrated that the combination of mesoporous conductive matrices with bimetallic phosphides could greatly improve the HER efficiency for electrocatalysis. [Display omitted] • FeCoP nanoparticles were uniformly anchored on N-doped carbon foam/CNT nanocomposite. • NC/CNT-FeCoP exhibits excellent HER activity in both alkaline and acid solution. • Carbon foam can improve the cycle stability for FeCoP. • A low cell potential of 1.68 V at 10 mA cm− 2 was obtained for overall water splitting. [ABSTRACT FROM AUTHOR]