Hydrogen production by energy-efficient water electrolysis is a green avenue for the development of contemporary society. However, the oxygen evolution reaction (OER) and the urea oxidation reaction (UOR) occurring at the anode are impeded by the sluggish reaction kinetics during the water-splitting process. Consequently, it is promising to develop bifunctional anodic electrocatalysts consisting of nonprecious metals. Herein, a bifunctional CoMn layered double hydroxide (LDH) was grown on nickel foam (NF) with a 1D-2D-3D hierarchical structure for efficient OER and UOR performance in alkaline solution. Owing to the significant synergistic effect of Mn doping and heterostructure engineering, the obtained Co1 Mn1 LDH/NF exhibits satisfactory OER activity with a low potential of 1.515 V to attain 10 mA cm-2 . Besides, the potential of the Co1 Mn1 LDH/NF catalyst for UOR at the same current density is only 1.326 V, which is much lower than those of its counterparts and most reported electrocatalysts. An urea electrolytic cell with a Co1 Mn1 LDH/NF anode and a Pt-C/NF cathode was established, and a low cell voltage of 1.354 V at 10 mA cm-2 was acquired. The optimized strategy may result in promising candidates for developing a new generation of bifunctional electrocatalysts for clean energy production.
Keywords: doping; electrochemistry; layered double hydroxides; oxygen evolution reaction; urea oxidation reaction.
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