Surface defect-engineered silver silicate/ceria p-n heterojunctions with a flower-like structure for boosting visible light photocatalysis with mechanistic insight
Surface defect-engineered silver silicate/ceria p-n heterojunctions with a flower-like structure for boosting visible light photocatalysis with mechanistic insight
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表面缺陷设计的硅酸银/二氧化铈 p-n 异质结，具有花状结构，可通过机械洞察增强可见光光催化作用
DOI：
10.1016/j.jcis.2019.12.128
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发表时间：
2020-03-22
影响因子：
9.9
通讯作者：
Liu, Xin
中科院分区：
文献类型：
--
作者：
Chen, Changfeng;Li, Mengru;Liu, Xin
光催化剂的载流子分离可以通过p-n异质结和表面缺陷工程来加速。采用原位沉积-沉淀法将p型银硅酸盐（Ag 6Si 2 O 7）纳米粒子均匀地修饰在由冰浴共沉淀法制备的n型CeO 2纳米花片上，成功制备了具有分级花状结构的新型银硅酸盐/CeO 2 p-n异质结光催化剂。Mott-Schottky曲线和形貌研究表明，Ag 6Si 2 O 7和CeO 2之间形成了p-n异质结。XPS和拉曼光谱证实，这导致异质结中产生大量的表面缺陷（Ce 3+离子或氧空位）。可见光照射下，复合材料的光催化性能得到显著提高，并可通过Ag 6Si 2 O 7的含量进行调节。当Ag 6Si 2 O 7负载量为40 wt%时，对无色污染物四环素、阳离子染料罗丹明B和阴离子染料甲基橙子的光催化去除效果最佳。通过各种表征技术证明，Ag 6Si 2 O 7纳米颗粒的装饰可以促进表面缺陷结构的形成，增加可见光捕获，并改善由两个半导体之间建立的电场驱动的电荷载流子的分离，从而导致显著增强的光催化活性。这项工作提供了一个可靠的策略，设计高效的p-n异质结的光催化应用在能源和环境。(C)2019爱思唯尔公司All rights reserved.
Charge carrier separation of photocatalysts can be accelerated by p-n heterojunctions and surface defect engineering. Here, novel silver silicate/ceria p-n heterojunction photocatalysts with a hierarchical flower-like structure were successfully synthesized through an in situ deposition-precipitation method in which p-type silver silicate (Ag6Si2O7) nanoparticles were evenly decorated on the sheets of n-type ceria (CeO2) nanoflowers prepared via an ice-bath coprecipitation process. Mott-Schottky plots and morphological studies indicated that p-n heterojunctions were constructed between Ag6Si2O7 and CeO2. This led to the generation of abundant surface defects (Ce3+ ions or oxygen vacancies) in the heterojunctions as confirmed by XPS and Raman. The photocatalytic properties are markedly improved under visible light irradiation and can be regulated by the Ag6Si2O7 content in the composites. The sample with 40 wt% Ag6Si2O7 loading had optimal photocatalytic elimination efficiency for the colorless contaminant tetracycline, the cationic dye rhodamine B, and the anionic dye methyl orange. As evidenced by various characterization techniques, the decoration of Ag6Si2O7 nanoparticles can promote the formation of a surface defect structure, increase visible light harvesting, and improve the separation of charge carriers driven by the electric field established between two semiconductors, thus leading to a remarkably enhanced photocatalytic activity. This work offers a reliable strategy for designing efficient p-n heterojunctions for photocatalytic applications in energy and the environment. (C) 2019 Elsevier Inc. All rights reserved.