利用光催化技术将CO₂转化为燃料有望解决能源危机和温室效应。Zn_1-2x(CuGa)_xGa₂S₄具有可见光响应及较高的导带电势, 从热力学上看是较为理想的CO₂还原材料, 但是其光催化CO₂还原活性仍然较低, 亟待从动力学角度提高其活性。本研究采用Zn_0.4(CuGa)_0.3Ga₂S₄与不同比例的CdS纳米颗粒复合, 制备了Zn_0.4(CuGa)_0.3Ga₂S₄/CdS异质结半导体材料。通过材料表征证明CdS在Zn_0.4(CuGa)_0.3Ga₂S₄微米颗粒上均匀生长并形成了全固态Z型异质结的复合结构。这种结构有效抑制了电子空穴对的复合, 保持了较高的还原电势, 有利于提高光催化性能。在溶液体系中, 所制备的Zn_0.4(CuGa)_0.3Ga₂S₄/CdS能够有效地将CO₂光催化还原为CO。研究表明, 当Zn_0.4(CuGa)_0.3Ga₂S₄与CdS的摩尔比为2 : 1时, 样品的光催化活性达到最优, 是Zn_0.4(CuGa)_0.3Ga₂S₄材料的1.7倍, CdS材料的1.6倍。本工作通过构造异质结构, 提高了Zn_0.4(CuGa)_0.3Ga₂S₄半导体材料的光催化CO₂还原活性, 对人工光合成材料的设计与制备具有较大的参考价值。

Conversion of CO₂ into fuels by photocatalysis is promising in solving the energy crisis and the greenhouse effect. Among various photocatalytic materials, Zn_1-2x(CuGa)_xGa₂S₄ materials possess visible light response and high conduction band potential, which are ideal CO₂ reduction materials from thermodynamics aspect. However, their photocatalytic CO₂ reduction activity is still low which is urgent to improve its activity in terms of kinetics. In this study, Zn_0.4(CuGa)_0.3Ga₂S₄ was synthesized and composited with CdS nanoparticles with different proportions to form Zn_0.4(CuGa)_0.3Ga₂S₄/CdS heterojunction photocatalysts. A series of characterizations suggest that CdS is uniformly grown on surface of Zn_0.4(CuGa)_0.3Ga₂S₄ microcrystals to form a Z-scheme type all-solid heterojunction composite materials. Such a structure effectively suppresses the recombination of electron-hole pairs and improve the photocatalytic performance. In the solution CO₂ reduction system, the as-prepared Zn_0.4(CuGa)_0.3Ga₂S₄/CdS can effectively reduce CO₂ into CO under visible light irradiation. The optimal molar ratio of Zn_0.4(CuGa)_0.3Ga₂S₄ and CdS in composite materials is 2 : 1, whose photocatalytic performance is 1.7 times of that of Zn_0.4(CuGa)_0.3Ga₂S₄/ CdS and 1.6 times of that of CdS. This work constructs all solid Z-scheme type Zn_0.4(CuGa)_0.3Ga₂S₄/CdS heterojunction materials with enhanced photocatalytic activity for CO₂ reduction, which is promising for designing novel photocatalysts in field of artificial photosynthesis.