Oxidation state of Mo affects dissolution and visible-light photocatalytic activity of MoO3 nanostructures
Oxidation state of Mo affects dissolution and visible-light photocatalytic activity of MoO3 nanostructures
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DOI：
10.1016/j.jcat.2019.11.035
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发表时间：
2020
影响因子：
7.3
通讯作者：
J. Peña-Bahamonde;Chunzheng Wu;S. Fanourakis;Stacey M. Louie;J. Bao;D. Rodrigues
中科院分区：
文献类型：
--
作者：
J. Peña-Bahamonde;Chunzheng Wu;S. Fanourakis;Stacey M. Louie;J. Bao;D. Rodrigues
具有可见光光催化活性的MoO3纳米材料的形状、溶解性和化学性质的作用在很大程度上仍然是未知的。在本研究中，我们调查的光降解性能和溶解产物的作用下，不同的pH值的三个MoO3纳米材料具有不同的形状和化学性质（纳米棒，纳米线，和纳米片）。我们发现，不同形态的MoO3呈现不同的溶解度行为，随着pH值的增加（最高的溶解度发生在pH 10），这种溶解取决于氧化状态和性质的Mo单键O键，而不仅仅是纳米结构的大小和形态。纳米粒子的溶解似乎有利地影响亚甲基蓝（MB）的脱色率，但不影响其光催化降解。重要的是区分MB变色与光催化降解，因为变色不仅涉及光催化降解，而且涉及吸附和离子络合过程。我们对MB的去除实验表明，纳米棒呈现出最好的基于光催化的降解活性，而呈现出最高溶解度的纳米线使MB脱色最快。通过对纳米MoO3产生的活性氧（ROS）进行定量分析，并通过测定ROS清除剂对MB光催化降解的抑制作用，研究了MoO3光催化降解MB的机理。根据结果，纳米材料中的光生空穴通过允许过氧化氢的产生来控制降解过程。研究表明，MoO3纳米结构的化学和物理性质，以及纳米结构的溶解过程，影响MoO3纳米结构的光催化性能。
The role of shape, dissolution, and chemical properties of MoO3nanomaterials with visible light photocatalytic activity are still largely unknown. In the present study, we investigate the photodegradative properties and role of dissolution products under different pH values of three MoO3nanomaterials with different shapes and chemical properties (nanorods, nanowires, and nanoplates). We show that different morphologies of MoO3present different solubility behaviors with increasing pH (with the highest solubility occurring at pH 10), and this dissolution depends on the oxidative state and nature of the Mosingle bondO bonds, not just the size and morphology of the nanostructures. Nanoparticle dissolution seems to favorably affect the discoloration rate of methylene blue (MB) but not its photocatalytic degradation. It is important to differentiate MB discoloration as opposed to photocatalytic degradation since discoloration involves not only photocatalytic degradation but also adsorption and ion complexation processes. Our experiments for the removal of MB show that the nanorods present the best photocatalytic-based degradation activity, while the nanowires, which present the highest dissolution, decolorize MB the fastest. MoO3photocatalytic degradation mechanism was investigated via the quantification of nanoparticle-produced reactive oxygen species (ROS) and measurement of MB photocatalytic degradation inhibition due to the presence of ROS scavengers. According to the results, photogenerated holes in the nanomaterial govern the degradative process by allowing production of hydrogen peroxide. This study demonstrates that MoO3nanostructure chemical and physical properties, as well as nanostructure dissolution process, influence the photocatalytic properties of MoO3nanostructures.