通过电化学-光还原法基于Bi板合成了Pd/BiF3薄膜,探究了不同质量分数的Pd 对BiF3薄膜光催化性能的影响。利用X射线衍射仪、扫描电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱对Pd/BiF3薄膜进行了表征分析。以模型污染物即罗丹明B(RhB)为光催化降解对象,考察了Pd/BiF3薄膜的光催化性能。表征结果显示,贵金属Pd均匀分布于BiF3薄膜表面上,当Pd的质量分数为2.0%时,Pd/BiF3薄膜表现出最佳的光催化降解RhB的性能,且光吸收带边发生明显的红移,带隙值由3.70 eV减小为3.03 eV。活性物种捕获实验表明,当Pd的质量分数为2.0%时,在Pd/BiF3薄膜光催化降解RhB的过程中,活性物种发挥的作用由大到小的顺序为羟基自由基(·OH)、超氧自由基(· O2-)、空穴(h +),并提出了Pd/BiF3薄膜光催化性能的增强机制。

In this study, the Pd/BiF₃ thin films are successfully prepared by the facile in-situ electrochemical-photoreduction method from the Bi plates, and the photocatalytic performances of the BiF₃ thin films with different mass fractions of Pd are investigated for comparison. The Pd/BiF₃ thin films are characterized by the XRD, SEM, XPS and UV-Vis DRS methods. The photocatalytic performance of Pd/BiF₃ thin films is investigated with rhodamine B (RhB) as the photocatalytic degradation object. Our characterization results indicate that when the noble metal Pd is loaded uniformly on the surface of BiF₃ thin films and the mass fraction of Pd is 2.0%, the Pd/BiF₃ thin films exhibit the optimal photocatalytic activity and stability for the degradation of RhB. In addition, there exist an obvious redshift of optical absorption bands and a decrease of bandgap from 3.70 eV to 3.03 eV. The capture experiment of active species confirms that when the mass fraction of Pd is 2.0%, the roles of the ·OH, · O2- and h ⁺ are from large to small during the photocatalytic degradation of RhB by Pd/BiF₃ films. Finally, an enhancement mechanism of photocatalytic performance of Pd/BiF₃ thin films is proposed.