Atomic-scale intercalation of N-doped carbon into monolayered MoSe2-Mo2C heterojunction as a highly efficiency hydrogen evolution reaction catalyst

Abstract

Two-dimensional (2D) MoSe2 is a promising catalyst for hydrogen evolution reaction (HER). However, the activity of MoSe2 needs to be enhanced further because of the limited exposed edge sites and low conductivity of pure MoSe2. Herein, a monolayer MoSe2-Mo2C heterojunction intercalated into N-doped carbon nanobelt layers (MoSe2-Mo2C/NC) is synthesized by in situ carbonizations of dodecylamine (DDA) inserted MoO3 nanobelts and followed by a selenylation treatment. Structural analysis revealed the presence of Mo2C broke the continuity of MoSe2, causing more edge sites for HER. Therefore, MoSe2-Mo2C/NC with high conductive NC layers and huge edge active sites of MoSe2-Mo2C layers exhibits considerable HER activities in acidic and alkaline environments, including low overpotentials and low Tafel slopes of 174/214 mV (at 10 mA cm−2), and 55/67 mV dec−1 in acid and alkaline solution, respectively, which are more active than the pure MoSe2/NC nanobelts and Mo2C/NC nanobelts. In addition, the MoSe2-Mo2C/NC has high stability with 3% current decrease during 10 h in 0.5 M H2SO4.