P-Doped MoSe₂/MoS₂ Heterojunctions Anchored on N-CNTs/Carbon Cloth with Abundant Interfaces and Defects for Effective Electrocatalytic Hydrogen Evolution

Abstract

Low-cost, stable, and high-efficiency electrocatalysts are highly demanded for large-scale hydrogen production by industrial-scale water electrolysis. The rational interface and defects engineering of the electrodes can effectively modify the active sites and promote electron transfer, thus facilitating the electrocatalytic splitting efficiency. In this work, spherical MoSe2/MoS2 heterojunction nanosheets are in situ anchored on nitrogen-doped carbon nanotubes/carbon cloth (N-CNTs/CC) struts. The porous and highly conductive N-CNTs/CC networks can improve the electron transfer, enlarge the exposed surface area, and facilitate the surface ion adsorption. Moreover, the influence of the Se/S ratio on the structure of the composites is also investigated. Afterward, abundant electron-rich defects and vacancies are introduced by the phosphorization process. The MoSe2/MoS2 heterojunctions with abundant interface can provide synergetic interactions and electronic modulations, while the PO43– dopant can expand the interlayer spacing and provide sufficient crystalline distortions and defects. Herein, the rational designed hierarchical P-MoSe0.5S1.5/N-CNTs/CC-2 composite exhibits a low overpotential (108.3 mV) at 10 mA cm–2, a small Tafel slope (58.6 mV dec–1), and excellent long-term catalytic and structural stability.