NiS-PdS/CdS光催化剂的水热法合成及其可见光分解水产氢性能

为提高太阳能转化效率, 高效响应可见光的光催化剂的研究十分必要. 本研究以硫化镉、氯化钯、醋酸镍和硫脲为原料, 利用水热法制备了NiS-PdS/CdS复合光催化剂. 通过X射线衍射(XRD)、紫外-可见光漫反射光谱(DRS)、透射电子显微镜(TEM)和光致发光(PL)光谱等手段对光催化剂进行了表征, 并在乳酸牺牲剂中对光解水制氢活性进行了测试. 结果表明: 助催化剂NiS 和PdS 能较好地分布在CdS 表面上, 形成共负载的NiS-PdS/CdS 光催化剂, 其可见光下的活性比CdS明显增强, 当NiS 和PdS 负载量分别在1.5%和0.41%(w)时, NiS-PdS/CdS获得最好活性, 最大产氢量达到6556 μmol·h^-1, 是CdS活性的7倍, 是NiS/CdS的近3倍, 测得在λ=420 nm时的表观量子效率为47.5%. 助催化剂NiS 和PdS分别起到传递光生电子和光生空穴的作用,两者共负载相比于单独负载, 能使光生载流子的迁移和分离效率更高, 因此提高了光催化产氢活性.

Hydrothermal Synthesis and Activity of NiS-PdS/CdS Catalysts for Photocatalytic Hydrogen Evolution under Visible Light Irradiation

To improve the solar energy transformation efficiency, it is necessary to study the efficiency of photocatalysts under visible light irradiation. In this study, the composite photocatalyst NiS-PdS/CdS has been developed using a hydrothermal method from the raw materials cadmium sulfide, palladium chloride, nickel acetate and thiourea. The characteristics of NiS-PdS/CdS were studied by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. In addition, the photocatalytic activities for water splitting were tested using lactic acid as the sacrificial reagent. The results showed that NiS and PdS dispersed well on the surface of CdS. The activity of NiS-PdS/CdS was much higher than that of CdS under visible light irradiation. When the loading amount of NiS and PdS reached 1.5% and 0.41% (w), respectively, NiS-PdS/ CdS showed the highest activity. The H₂ evolution rate increased up to 6556 μmol·h^-1, which was six times higher than that of unloaded CdS and nearly two times higher than that of NiS/CdS. The apparent quantum yield was 47.5% (λ=420 nm). The co-catalysts NiS and PdS prompted the transfer of photogenerated electrons and holes, respectively. Compared with single-loading, co-loading the two co-catalysts could transfer and separate charge carriers more efficiently, resulting in enhancement of the activity for photocatalytic hydrogen production.