Ru-doping induced lattice strain in hetero-phase Ni2P–Ni12P5 arrays enables simultaneous efficient energy-saving hydrogen generation and formate electrosynthesis

Abstract

Coupling the hydrogen evolution reaction (HER) with the glycerol oxidation reaction (GOR) can efficiently suppress the sluggish oxygen evolution reaction (OER), boost hydrogen production efficiency and meanwhile obtain glycerol-derived value-added anodic products. Developing active and robust HER-GOR bifunctional electrocatalysts is of vital significance for constructing a water–glycerol co-electrolysis system. Herein, Ru-doped heterostructured nickel phosphide/nitrogen-doped carbon (Ru–Ni_xP_y/N–C) hybrid nanosheet arrays were fabricated by controlled phosphorization of NiRu-based metal–organic framework nanosheet array precursors. With the synergism of the hetero-phase Ni₂P–Ni₁₂P₅ interface effect and Ru-doping induced strain effect, the Ru–Ni_xP_y/N–C arrays grown on Ni foam (Ru–Ni_xP_y/N–C/NF) could efficiently electrocatalyze both the HER (−10 mA cm⁻²@ −0.031 V vs. RHE) and GOR (10 mA cm⁻² @1.32 V vs. RHE). Remarkably, the Ru–Ni_xP_y/N–C/NF||Ru–Ni_xP_y/N–C/NF two-electrode system could enable simultaneous efficient H₂ generation and formate electrosynthesis from a 1 M KOH solution containing 0.1 M glycerol, deriving a 10 mA cm⁻² current density at a low cell voltage of 1.36 V.