Synergized Ni/NiOx heterojunction encapsulated by N-doped graphitized carbon core@shell electrocatalyst for efficient hydrogen production

Abstract

• Facile preparation strategy based on the self-assembly and in-suit synthesis. • The tunable composition of Ni/NiO x by optimizing calcination process. • Glycine as carbon and nitrogen sources to form N -doped carbon shell in one step. • The Ni/NiO x @NC electrocatalyst exhibits remarkable electrocatalytic performance. In this paper, based on the self-assembly of nickel glycinate, the Ni/NiO x heterojunction encapsulated by nitrogen-doped graphitized carbon shells (Ni/NiO x @NC) was prepared via two facile steps for hydrogen production. Attributed to the synergistic catalysis of the well-proportioned Ni/NiO x heterojunction, the accelerated electron transport and the protective effect of the NC layers, the prepared Ni/NiO x @NC catalysts exhibited good electrocatalytic performance, with a minimum overpotential of 173 mV (vs RHE) at the current density of 10 mA cm −2 in 1 M KOH and the slight performance degradation after continuous cyclic voltammetry sweeps for 6000 cycles.