Preparation of MnS with Different Crystal Phases for Photocatalytic H₂ Production from H₂S

Abstract

Cubic α-MnS and hexagonal γ-MnS were successfully prepared by a one-pot solvothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and UV-Vis absorption spectrum were used to investigate the phase, microstructure, morphology, and optical property of the obtained samples. The photocatalytic H 2 production performances from H 2 S of α-MnS and γ-MnS were evaluated both under visible light (λ > 420 nm) and UV-Vis light irradiation. The results revealed that both α-MnS and γ-MnS possess photo-splitting H 2 S activity under visible light, and the metastable state γ-MnS showed better photocatalytic H 2 evolution performance (23.38 μmol/(g•h)) than the stable form α-MnS (4.24 μmol/(g•h)). Comparing the photocatalytic activity under visible light, it was found that the hydrogen production rate of α, γ-MnS under the full spectrum irradiation increased re-第 12 期 淡 猛, 等: 不同晶相 MnS 制备及光解 H 2 S 制氢性能研究 1309 markably. A maximum H 2 production rate of 2272.69 μmol/(g•h) was achieved over γ-MnS under the full spectrum irradiation. It is noteworthy that during the process of 6 h photocatalytic testing, α, γ-MnS displayed a good stability and resistance to the photocorrosion. In addition, the catalytic mechanism of α, γ-MnS was investigated. Finally, the reason for the difference in photocatalytic activity between these two MnS phases was explored.