Hydrothermal Synthesis of La-MoS2 and Its Catalytic Activity for Improved Hydrogen Evolution Reaction

Abstract

Herein, we report the synthesis and characterization of lanthanum-doped MoS2 (La-MoS2) via a hydrothermal route. The synthesized La-MoS2 was characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) techniques. The band gap of La-MoS2 was observed to be 1.68 eV, compared to 1.80 eV for synthesized MoS2. In the photoluminescence (PL) spectra, a decrease in the intensity was observed for La-MoS2 compared to MoS2, which suggests that due to doping with charged La3+, separation increases. The as-synthesized MoS2 and La-MoS2 were used for photocatalytic hydrogen evolution reactions (HERs), exhibiting 928 µmol·g−1 evolution of H2 in five hours for a 10 mg dose of La-MoS2, compared to 612 µmol·g−1 for MoS2. A 50 mg mass of the catalyst (La-MoS2) exhibited enhanced H2 production of 1670 µmol·g−1 after five hours. The higher rate of the HER for La-MoS2 is because of doping with La3+. The photocatalytic hydrogen evolution performance of La-MoS2 was also evaluated for different doses of La-MoS2 exhibiting reusability up to the fourth cycle, showing potential applications of La-MoS2 in hydrogen evolution reactions. Mechanistic aspects of the HER on the surface of La-MoS2 have also been discussed.