MoS2/NiVFe crystalline/amorphous heterostructure induced electronic modulation for efficient neutral-alkaline hydrogen evolution

Abstract

MoS2 is attractive for electrocatalytic hydrogen evolution reaction (HER) as an inexpensive transition metal-based electrocatalyst, however, its catalytic performance within a wide pH range is still challenging. Herein, NiVFe layered double hydroxide (LDH) modified MoS2 (MoS2/NiVFe) is developed by a two-step hydrothermal method to form a crystal-amorphous heterostrctural electrocatalyst. The crystal-amorphous heterostrcture is demonstrated to provide a large electrochemically active surface area to enhance the active sites and expedite the electron transfer. More importantly, a strong electronic modulation effect is revealed by XPS and theoretical calculations that electrons in NiVFe-LDH transfer to MoS2, which results in high-valent Ni-site to attract -OH and electron-rich S-site to adsorb -H, significantly reducing the barriers of water splitting. As a result, at 10 mA cm−2 in alkaline and neutral media, the MoS2/NiVFe electrocatalyst exhibits low overpotentials for HER of 78 and 141 mV, respectively. A remarkable activity towards OER is also achieved accompanied with an impressive stability. When applied as both electrodes for overall water separation, it only needs a low cell voltage of 1.47 V for MoS2/NiVFe to provide a current density of 10 mA cm−2 in 1.0 M KOH. This study provides an efficient method for designing MoS2-based electrocatalysts for HER within a broad pH range.