Enhanced Mass Transfer of Oxygen through a Gas–Liquid–Solid Interface for Photocatalytic Hydrogen Peroxide Production
Enhanced Mass Transfer of Oxygen through a Gas–Liquid–Solid Interface for Photocatalytic Hydrogen Peroxide Production
复制标题
DOI：
10.1002/adfm.202106120
复制
发表时间：
2021-09
影响因子：
19
通讯作者：
Lejing Li;Liangpang Xu;Zhuofeng Hu;Jimmy C. Yu
中科院分区：
文献类型：
--
作者：
Lejing Li;Liangpang Xu;Zhuofeng Hu;Jimmy C. Yu
太阳能驱动的光催化氧还原是生产过氧化氢（H2 O2）的潜在可持续途径。然而，这种方法的缺点是氧气在水中的溶解度有限且扩散缓慢。另一个问题是，大多数光催化氧还原系统仅用水不能很好地工作。它们通常需要添加牺牲剂，例如醇。在此，报道了一种基于共价有机框架（COF）的光催化剂，其可以在可见光照射下在纯水中有效地将O2还原为H2 O2。对于H2 O2生成，实现了0.76%的太阳能-化学转化。更重要的是，三苯基苯-二甲氧基苯甲醛-COF的疏水性和介孔性质允许在将该催化剂负载到多孔基底上时形成三相界面（气-液-固）。通过克服水中O2的传质限制，在三相界面处H2 O2的产生速率达到1.29 mmol gcat−1 h−1。值得注意的是，该速率比两相系统（液-固）中的速率高15倍。光电化学测试表明，产率的增加与传质速率的提高和较高的界面O2浓度密切相关。此外，三苯基苯部分被确定为基于理论计算的反应位点。
Solar‐driven photocatalytic oxygen reduction is a potentially sustainable route for the production of hydrogen peroxide (H2O2). However, this approach suffers from the limited solubility and slow diffusion of oxygen in water. Another problem is that most photocatalytic oxygen reduction systems do not work well with just water. They often require the addition of sacrificial agents such as alcohols. Here, a covalent organic framework (COF)‐based photocatalyst that can reduce O2 to H2O2 efficiently in pure water under visible‐light irradiation is reported. A solar‐to‐chemical conversion of 0.76% is achieved for H2O2 generation. More importantly, the hydrophobic and mesoporous properties of triphenylbenzene‐dimethoxyterephthaldehyde‐COF allow the formation of a triphase interface (gas–liquid–solid) when loading this catalyst onto a porous substrate. The H2O2 production rate reaches ≈2.9 mmol gcat−1 h−1 at the triphase interface by overcoming the mass‐transfer limitation of O2 in water. Notably, this rate is 15 times higher than that in a diphase system (liquid–solid). The photoelectrochemical tests reveal that the increase in yield is closely related to the enhanced mass‐transfer rate and the higher interfacial O2 concentration. Furthermore, the triphenylbenzene part is identified as the reactive site based on theoretical calculations.