Umar M, Mahmood Nasir, Awan Saif Ullah, Fatima Sabeen, Mahmood Asif, Rizwan Syed
Physics Characterization and Simulations Lab (PCSL), School of Natural Sciences (SNS), National University of Science and Technology (NUST) Islamabad 44000 Pakistan
School of Electrical and Computer Engineering, RMIT University 124 La Trobe Street 3001 Melbourne Victoria Australia.
RSC Adv. 2019 May 31;9(30):17148-17156. doi: 10.1039/c9ra03064f. eCollection 2019 May 29.
Development of efficient visible light photocatalysts for water purification and hydrogen production by water splitting has been quite challenging. The activities of visible light photocatalysts are generally controlled by the extent of absorption of incident light, band gap, exposure of catalyst surface to incident light and adsorbing species. Here, we have synthesized nanostructured, La and Se co-doped bismuth ferrite (BLFSO) nanosheets using double solvent sol-gel and co-precipitation methods. Structural analysis revealed that the La and Se co-doped BFO BiLaFe Se O (BLFSO) transformed from perovskite rhombohedral to orthorhombic phase. As a result of co-doping and phase transition, a significant decrease in the band gap from 2.04 eV to 1.76 eV was observed for BLFSO-50% (having Se doping of 50%) which requires less energy during transfer of electrons from the valence to the conduction band and ultimately enhances the photocatalytic activity. Moreover, upon increase in Se doping, the BLFSO morphology gradually changed from particles to nanosheets. Among various products, BLFSO-50% exhibited the highest photocatalytic activities under visible light owing to homogenous phase distribution, regular sheet type morphology and larger contact with dye containing solutions. In summary, La, Se co-doping is an effective approach to tune the electronic structure of photocatalysts for visible light photocatalysis.
开发用于水净化和通过水分解制氢的高效可见光光催化剂一直颇具挑战性。可见光光催化剂的活性通常受入射光吸收程度、带隙、催化剂表面对入射光的暴露以及吸附物种的控制。在此，我们使用双溶剂溶胶 - 凝胶法和共沉淀法合成了纳米结构的镧（La）和硒（Se）共掺杂的铋铁氧体（BLFSO）纳米片。结构分析表明，La和Se共掺杂的BFO（BiLaFeSeO，即BLFSO）从钙钛矿菱面体相转变为正交相。由于共掺杂和相变，对于BLFSO - 50%（Se掺杂量为50%），观察到带隙从2.04 eV显著降低至1.76 eV，这在电子从价带转移到导带的过程中需要较少的能量，最终提高了光催化活性。此外，随着Se掺杂量的增加，BLFSO的形态逐渐从颗粒变为纳米片。在各种产物中，BLFSO - 50%由于其均匀的相分布、规则的片状形态以及与含染料溶液的更大接触面积，在可见光下表现出最高的光催化活性。总之，La、Se共掺杂是一种调节光催化剂电子结构以用于可见光光催化的有效方法。
