Materials Science

CLC number: TB333

Preparation and Characterization of Magnetic Ag₃PO₄/CoFe_1.95Dy_0.05O₄ S-Scheme Heterojunction

磁性Ag₃PO₄/CoFe_1.95Dy_0.05O₄ S型异质结的制备与表征

School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232038, Anhui, China

^† Corresponding author. E-mail: 13956468746@163.com; 573543828@qq.com

Received: 1 May 2024

Abstract

The development of efficient photocatalysts is of paramount importance for the photocatalytic degradation of organic compounds. An effective approach is to construct heterojunctions with tight interface structures in order to enhance interfacial charge transfer and achieve high photocatalytic activity. A magnetically recyclable photocatalytic composite, comprising Ag₃PO₄/CoFe_1.95Dy_0.05O₄ (AP/CFDO) S-scheme heterojunction, was synthesized using a simple hydrothermal method. The composition, microstructure and photoelectrochemical properties of the nanocomposites were comprehensively characterized by various advanced characterization methods. The photocatalytic activity of the AP/CFDO nanocomposites was investigated by subjecting methylene blue (MB) to degradation. The results demonstrated that AP/CFDO exhibited high degradation efficiency in the catalytic degradation of MB, with a degradation efficiency of 99.8% achieved within 30 min under visible light irradiation. Furthermore, after five repeated experiments, the degradation efficiency of MB under visible light irradiation remained at 90%. Furthermore, the degradation process followed the first-order kinetic reaction model, with a rate constant of 0.140 42 min^-1, which was 2.47 and 10.77 times that of Ag₃PO₄ (AP, 0.056 78 min^-1) and CFDO (0.013 04 min^-1). This phenomenon can be attributed to the S-scheme heterojunction constructed between AP and CFDO, which enables the effective spatial separation and transfer of photogenerated carriers. Finally, the reaction mechanism of photocatalytic degradation of MB was studied by adding different free radical scavengers. The results of capture experiments showed that superoxide radicals and hydroxyl radicals were the main active substances in the process of photocatalytic degradation.

摘要

开发高效的光催化剂对有机原料的光催化降解至关重要。一种有效的方法是构建具有紧密界面结构的异质结，以增强界面电荷转移，实现较高的光催化活性。采用简单的水热法合成了一种磁性Ag₃PO₄/CoFe_1.95Dy_0.05O₄(AP/CFDO)S型异质结光催化复合材料，对其组成、微观结构和光电化学性质进行了表征。通过亚甲基蓝(MB)降解，研究了AP/CFDO的光催化活性。结果表明，AP/CFDO在MB的催化降解过程中具有较高的降解效率，在可见光照射下30 min范围内降解效率达到99.8%。此外，经过5次重复实验,MB在可见光照射下的降解效率仍保持在90%。降解过程遵循一级动力学反应模型,速率常数为0.140 42 min^-1，分别为AP(0.056 78 min^-1)和CFDO(0.013 04 min^-1)的2.47倍和10.77倍，这可以归因于AP和CFDO之间构建的S型异质结，使光生载流子能够实现有效的空间分离和转移。最后，通过添加不同的自由基清除剂，研究了光催化降解MB的反应机理。捕获实验结果表明，超氧自由基(·O${}_{\mathrm{2}}^{-}$)和羟基自由基(·OH)是光催化降解过程中的主要活性物质。