Alam U, Kumar S, Bahnemann D, Koch J, Tegenkamp C, Muneer M
Department of Chemistry, Aligarh Muslim University, Aligarh-202002, India.
Phys Chem Chem Phys. 2018 Feb 7;20(6):4538-4545. doi: 10.1039/c7cp08206a.
The photocatalytic performance of MoO is limited due to its weak visible light absorption ability and quick recombination of charge carriers. In the present work, we report the facile synthesis of Fe(iii)-grafted MoO nanorods using a hydrothermal method followed by an impregnation technique with the aim of enhancing the light harvesting ability and photocatalytic efficiency of MoO. The prepared samples were characterized through the standard analytical techniques of XRD, SEM-EDS, TEM, XPS, UV-Vis-DRS, FT-IR, TG-DTA and PL spectrophotometry. XPS and TEM analyses reveal that Fe(iii) ions are successfully grafted onto the surface of the MoO nanorod with intimate interfacial contact. The photocatalytic performances of the prepared samples were investigated by studying the degradation of methylene blue (MB), rhodamine B (RhB) and 4-nitrophenol (4-NP) under visible light irradiation. The surface-modified MoO with Fe(iii) ions showed excellent photocatalytic activity towards the degradation of the above-mentioned pollutants, where Fe(iii) ions act as effective cocatalytic sites to produce hydroxyl radicals through multi-electron reduction of oxygen molecules. The improved photocatalytic activity could be ascribed to the effective separation of charge carriers and efficient production of hydroxyl radicals via the rapid capture of electrons by Fe(iii) through a well-known photoinduced interfacial charge transfer mechanism. Based on scavenger analysis study, a mechanism for the enhanced photocatalytic activity has been discussed and proposed. The concept of surface grafting onto large bandgap semiconductors with ubiquitous elements opens up a new avenue for the development of visible-light-responsive photocatalysts with excellent photocatalytic activity.
由于MoO可见光吸收能力较弱且电荷载流子快速复合，其光催化性能受到限制。在本工作中，我们报道了采用水热法随后结合浸渍技术简便合成Fe(III)接枝的MoO纳米棒，目的是提高MoO的光捕获能力和光催化效率。通过XRD、SEM-EDS、TEM、XPS、UV-Vis-DRS、FT-IR、TG-DTA和PL分光光度法等标准分析技术对制备的样品进行了表征。XPS和TEM分析表明，Fe(III)离子成功接枝到MoO纳米棒表面，界面接触紧密。通过研究亚甲基蓝(MB)、罗丹明B(RhB)和4-硝基苯酚(4-NP)在可见光照射下的降解情况，考察了制备样品的光催化性能。用Fe(III)离子表面改性的MoO对上述污染物的降解表现出优异的光催化活性，其中Fe(III)离子作为有效的共催化位点，通过氧分子的多电子还原产生羟基自由基。光催化活性的提高可归因于电荷载流子的有效分离以及通过众所周知的光诱导界面电荷转移机制，Fe(III)快速捕获电子从而高效产生羟基自由基。基于清除剂分析研究，讨论并提出了光催化活性增强的机制。用常见元素对大带隙半导体进行表面接枝的概念为开发具有优异光催化活性的可见光响应光催化剂开辟了一条新途径。
