Saliba Daniel, El Jamal Salah Eddin, Jonderian Antranik, Ammar Manal, Hmadeh Mohamad, Al-Ghoul Mazen
Department of Chemistry, McGill University 801 Sherbrooke St W Montreal Quebec H3A 0B8 Canada.
Department of Chemistry, American University of Beirut P. O. Box 11-0236, Riad El-Solh 1107 2020 Beirut Lebanon
RSC Adv. 2020 Nov 26;10(70):43066-43074. doi: 10.1039/d0ra08006c. eCollection 2020 Nov 23.
The distinctive layered structure, chemical stability and tunability of layered double hydroxides (LDHs) have led to extensive investigations in various areas of photocatalysis, including photocatalytic water splitting, carbon dioxide photoreduction, and degradation of organic pollutants. Here, a series of visible light active cadmium-aluminum layered double hydroxides (CdAl LDHs) with various Cd : Al ratios is synthesized the reaction-diffusion framework (RDF) leading thereby to a hierarchal spherical structure of the LDH. The aim of this study is to develop an optimal CdAl LDH photocatalyst that is activated by solar light irradiation and tested for methylene blue (MB) degradation. The structural and physicochemical properties of the synthesized materials are determined by several imaging and spectroscopic techniques. The photocatalytic study reveals a strong dependence of the photocatalytic activity of the CdAl LDH on the cationic ratio with an optimal performance at a ratio Cd : Al equal to 3 : 1. A mechanism is proposed whereby the activity is ascribed to the formation of intermediate reactive oxidative species (ROS) during the photodegradation reactions and scrutinised by invoking different ROS quenchers and corroborated by density functional theory (DFT) calculations.
层状双氢氧化物（LDHs）独特的层状结构、化学稳定性和可调控性，已引发了在光催化各个领域的广泛研究，包括光催化水分解、二氧化碳光还原以及有机污染物降解。在此，通过反应扩散框架（RDF）合成了一系列具有不同镉铝比的可见光活性镉铝层状双氢氧化物（CdAl LDHs），从而形成了LDH的分级球形结构。本研究的目的是开发一种经太阳光照射活化的最佳CdAl LDH光催化剂，并对其降解亚甲基蓝（MB）的性能进行测试。通过多种成像和光谱技术确定了合成材料的结构和物理化学性质。光催化研究表明，CdAl LDH的光催化活性强烈依赖于阳离子比例，在镉铝比为3:1时具有最佳性能。提出了一种机制，即活性归因于光降解反应过程中中间活性氧化物种（ROS）的形成，并通过使用不同的ROS猝灭剂进行了仔细研究，同时得到了密度泛函理论（DFT）计算的证实。
