Luo Kaiyi, Li Jing, Hu Wenyu, Li Han, Zhang Qiuping, Yuan Huan, Yu Fei, Xu Ming, Xu Shuyan
College of Electrical & Information Engineering & Key Lab of Information Materials of Sichuan Province, Southwest University for Nationalities, Chengdu 610041, China.
Plasma Sources and Application Center, Nanyang Technological University, Singapore 37616, Singapore.
Nanomaterials (Basel). 2020 Sep 29;10(10):1946. doi: 10.3390/nano10101946.
The construction of heterostructured photocatalyst with an appropriate energy band structure will help realize highly efficient photo-excited charge separation. In this study, ternary CuO/CeO/ZnO nano-particle (NP) composites were synthesized by a facile two-step sol-gel method, which exhibit significantly enhanced photocatalytic degradation performance for various organic pollutants under UV and visible light excitation. The photo-responses to both UV and visible light, as well as the visible light absorption and utilization rates of ZnO are found to be synergistically intensified by CeO and CuO co-coupling. The first-order kinetic constants (K) of 3%CuO/CeO/ZnO for methylene blue (MB) degradation are ~3.9, ~4.1 and ~4.8 times higher than ZnO under UV light, visible light and simulated sunlight illumination, respectively. The roles of CuO and CeO in optical properties and photo-degradation under UV and visible light were explored. Besides, the photogenic holes (h) of ZnO, CeO, and the produced hydroxyl radicals (·OH) are proved to be the main active species under UV light. Dissimilarly, under visible light, the superoxide radicals (·O) formed by the reactions between oxygen molecules and the photo-generated electrons (e) of CuO moving towards the catalysts surface are also found to be important for promoting dye decomposition. The improved photo-responses, the well-matched band structure that facilitates charge transfer processes, and the highly efficient utilization of the photo-excited carriers of the ternary nano-heterostructure are suggested to be the key factors for the remarkable enhancement of photocatalytic performance of ZnO nano-photocatalyst. This work offers a low-cost strategy to acquire highly active UV and visible light-driven photocatalyst.
构建具有合适能带结构的异质结构光催化剂将有助于实现高效的光激发电荷分离。在本研究中，通过简便的两步溶胶-凝胶法合成了三元CuO/CeO/ZnO纳米颗粒（NP）复合材料，该复合材料在紫外光和可见光激发下对各种有机污染物表现出显著增强的光催化降解性能。发现CeO和CuO的共耦合协同增强了ZnO对紫外光和可见光的光响应以及可见光吸收和利用率。在紫外光、可见光和模拟太阳光照射下，3%CuO/CeO/ZnO降解亚甲基蓝（MB）的一级动力学常数（K）分别比ZnO高约3.9倍、4.1倍和4.8倍。探讨了CuO和CeO在紫外光和可见光下的光学性质和光降解中的作用。此外，证明了ZnO、CeO的光生空穴（h）以及产生的羟基自由基（·OH）是紫外光下的主要活性物种。不同的是，在可见光下，氧分子与向催化剂表面移动的CuO光生电子（e）反应形成的超氧自由基（·O）也被发现对促进染料分解很重要。三元纳米异质结构改善的光响应、促进电荷转移过程的匹配良好的能带结构以及光激发载流子的高效利用被认为是ZnO纳米光催化剂光催化性能显著增强的关键因素。这项工作提供了一种低成本策略来获得高活性紫外光和可见光驱动的光催化剂。
