Mn doped CoP nanoparticle clusters: an efficient electrocatalyst for hydrogen evolution reaction

Abstract

Since metal cations in layered double hydroxide materials (LDHs) can be substituted partially by M³⁺ ions, LDHs can be applied as ideal precursors for the preparation of foreign metal doped phosphides. In this work, a Mn doped cobalt phosphide (CoP) electrocatalyst coated electrode was prepared from CoMn LDH precursors by a unipolar pulse electro-deposition (UPED) method combined with a thermal phosphorization process. Experimental results indicated that the Mn-CoP coated electrode needed a much lower overpotential than the original CoP coated one in the same current density for hydrogen evolution reaction (HER) in water splitting. The CoP coated electrode required an overpotential of 127 mV to support 10 mA cm⁻² current density in 0.5 M H₂SO₄ solution, and in contrast, the Mn-CoP coated one required only 108 mV overpotential to support the same current density. Furthermore, in the 1.0 M KOH solution, the Mn-CoP coated electrode revealed better performance, and the overpotential at 10 mA cm⁻² current density was reduced to as low as 95 mV.