Synthesis And Photocatalytic Properties Of Ternary Metal Chalcogenide Containing Indium

Photocatalytic H₂ from water splitting using semiconductor photocatalyst is a promising and challenging issue in the conversion of solar energy into chemical energy.In this paper,trigonal phase ZnIn₂S₄ and cubic AgIn₅S₈ were synthesized by a one-step high-temperature solid state method,and studied the photocatalytic properties of them.In addition,since ZnNb₂O₆ is an ultraviolet-responsive photocatalyst,so we fabricated the solid solution Zn_1-x-x Mn_x Nb₂O₆ to adjust its band gap structure.ZnIn₂S₄ is a typical semiconductor photocatalyst.But ZnIn₂S₄ has the properties of Polymorphism,including hexagonal phase（P6₃mc,a=3.85?,c=24.68?）,cubic phase（Fd-3m,a=10.62?）,trigonal phase（R-3m,a=3.86?,c=37.01?）.For the first time,we prepared the trigonal ZnIn₂S₄（described using the rhombohedral lattice R-3m）by typical solid state reaction at 700°C in an evacuated quartz tube.It is highly crystallized indicated by sharp reflection peaks in X-ray diffraction pattern,and its suitable band structure ensure the capability of visible light driven photocatalytic H₂ generation in Na₂S and Na₂SO₃ aqueous solution.The as-prepared ZnIn₂S₄ possesses a stable photocatalytic H₂ generation rate of³2μmol/g/h for 5 cycles,which could be significantly enhanced to 1582μmol/g/h by co-loading 0.5 wt%Pt and 0.5 wt%Pd.By varying the incident beam intensity,the apparent quantum of photocatalytic water reduction for trigonal ZnIn₂S₄ was evaluated and optimized to 3.57（1）%at 405 nm.AgIn₅S₈,a narrow band gap semiconductor potocatalyst,was widely used in photocatalytic water splitting,but rarely used in nitrite reduction.In this study,we controlled the reaction atmosphere and temperature to get a pure sample of AgIn₅S₈,applied it to photocatalytic nitrite reduction.At last,we obtained the pure sample under the atmosphere of Ar（1%H₂）at 600℃.XRD was employed to determine the composition of it.Moreover,under the irradiation of the UV light,the sample possessed the property for nitrite reduction,and the selectivity of N₂ was more than 90%.Zn_1-xMn_x Nb₂O₆ solid solution:ZnNb₂O₆ is a semiconductor photocatalyst which can product hydrogen under UV light irradiation,MnNb₂O₆ with a narrow bang gap and can be used to the degradation of organic pollution.Both of them with a structure of niobite,the radius of the Mn²⁺and Zn²⁺are similar.So we prepared the solid solution of Zn_1-xMn_x Nb₂O₆.XRD was regularly utilized to determine the phase of the as-synthesized Zn_1-xMn_x Nb₂O₆（x=0.05,0.1,0.15,0.2,0.25,0.3,0.4…0.9,1）.The photocatalytic experiments revealed that it is not successfully to modify the potential of bang gap of ZnNb₂O₆ when x in the range of 0.05⁰.2.