Pd cocatalyst on Sm-doped BiFeO3 nanoparticles: synergetic effect of a Pd cocatalyst and samarium doping on photocatalysis
Pd cocatalyst on Sm-doped BiFeO3 nanoparticles: synergetic effect of a Pd cocatalyst and samarium doping on photocatalysis
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Sm 掺杂 BiFeO3 纳米颗粒上的 Pd 助催化剂：Pd 助催化剂和钐掺杂对光催化的协同作用
DOI：
10.1039/c6ra01140c
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发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
Huang Yuexiang
中科院分区：
文献类型：
--
作者：
Wang Sen;Chen Da;Niu Feng;Zhang Ning;Qin Laishun;Huang Yuexiang
为了探索稀土掺杂和贵金属助催化剂负载对BiFeO 3（BFO）光催化活性的协同作用，采用溶胶-凝胶法和浸渍法制备了Pd负载量不同的Pd助催化剂和Sm掺杂的BFO（Pd/BSFO）复合光催化剂.实验结果表明，Sm的取代使BFO的菱面体结构发生了畸变，Pd助催化剂纳米粒子均匀地沉积在BSFO颗粒表面，并在Pd与BSFO的界面处形成了异质结.与BFO、BSFO和Pd/BFO样品相比，Pd/BSFO样品表现出改善的紫外-可见光谱吸收能力和显著增强的光催化活性，用于光降解甲基橙子或无色化合物（即，苯酚）在可见光照射下。当BSFO表面钯负载量为1.5wt%时，光催化降解效率最佳。光致发光（PL）发射光谱表明，Pd/BSFO光催化剂的光吸收增强，有效的电荷转移和分离，以及Sm掺杂陷阱能级导致的光生电子-空穴对的复合受到抑制，以及Pd/BSFO中BSFO与Pd助催化剂之间肖特基势垒的异质结形成，光电流作用谱和电化学阻抗谱。结合能带计算和捕集实验，对光催化机理进行了探讨。
To explore the synergetic effect of rare earth doping and noble metal cocatalyst loading on the photocatalytic activity of BiFeO3 (BFO), in this work, novel Pd cocatalyst-loaded and Sm-doped BFO (Pd/BSFO) composite photocatalysts containing different Pd loading contents were successfully prepared by using a sol–gel method followed by an impregnation process. The experimental results revealed that the rhombohedral structure of BFO was distorted by Sm substitution, and Pd cocatalyst nanoparticles were uniformly deposited on the surface of BSFO particles with the formation of a heterojunction at the interface between Pd and BSFO. Compared to the BFO, BSFO and Pd/BFO sample, the Pd/BSFO samples exhibited improved UV-vis spectral absorption ability and significantly enhanced photocatalytic activities for the photodegradation of methyl orange or a colorless compound (i.e., phenol) under visible light irradiation. When the Pd loading amount on the surface of BSFO was 1.5 wt%, the optimal photocatalytic degradation efficiency was achieved. The enhanced photocatalytic activity of the Pd/BSFO photocatalyst could be attributed to the increased optical absorption, the efficient charge transfer and separation as well as the suppressed recombination of photogenerated electron–hole pairs derived from the Sm dopant trapping level and the heterojunction formation of the Schottky barrier between BSFO and the Pd cocatalyst in Pd/BSFO, as verified by photoluminescence (PL) emission spectra, photocurrent action spectra and electrochemical impedance spectra (EIS). On the basis of the calculated energy bands and trapping experiments, the photocatalytic mechanism was also discussed.