以磁場增強溴氧化鉍用於光催化氮還原反應之探討

Magnetic-field-enhanced Photocatalytic Nitrogen Reduction Reaction by Bismuth Oxybromide

林毓澍(Lin Yu-Shu)

指導教授 ： 陳家俊

國立臺灣師範大學/理學院/化學系/碩士(2022年)

https://doi.org/10.6345/NTNU202200609

摘要

氨是在人類社會中很重要化合物之一，而且有許多用途。由於氨的大量需求量以及面對能源短缺和環保等環境問題，在氨的製備過程中減少能源的使用和避免環境的污染並如何提升生產的效率已經是非常熱門的研究。本篇利用光催化的方法進行氮還原反應產生作為氨生產的方式。
鹵氧化鉍是一類鉍為基底的半導體二維材料，由於能隙容易控制的特性，常被用來做光催化應用。材料改良的常見的手法比如缺陷、原子摻雜、異質結等等，經常出現在光催化的應用，同樣也常出現在鹵氧化鉍的催化中。本篇使用系列中的溴氧化鉍進行光催化氮還原反應，該材料的合成方法選擇使用簡單、快速且高產率的水熱法的方式進行合成。氮還原反應是在水的環境下且不使用犧牲劑，並利用模擬太陽光作為光源來進行。得出來的原始溴氧化鉍的產率只有2.5 μmol hr-1 g-1。為了提升效率而對材料進行鐵原子的摻雜，並用EDX、XRD、EPR鑑定有成功在材料內摻雜鐵原子。摻雜後產率為5.5 μmol hr-1 g-1，效率有提升。不過為了更好的效率，在摻雜鐵原子後的材料加上磁場進行反應。其反應後的產率達到15 μmol hr-1 g-1，是原始BiOBr的7到8倍，外加磁場對BiOBr的效率有提升。

關鍵字

鹵素化鉍 ； 光催化 ； 氮還原反應 ； 電子-自旋極化

並列摘要

Ammonia are one of the important compounds in human society with many uses. Due to the high demand of ammonia and environmental problem such as energy crisis and eco-friendly, decreasing consuming energy, avoiding environment pollution and enhance efficiency in ammonia process are very popular research for nowadays. We use photocatalysis nitrogen reduction reaction method to produce ammonia.
Bismuth oxyhalide is a kind of bismuth-based semi-conductor two- dimensional material. Because of tunable bandgap, it is usually used in photocatalysis process. To improve material efficiency, the method such as defect manufacture, atom doping and heterojunction are the technique often be used in photocatalysis application. Bismuth oxyhalide also can improve efficiency by these methods. In this article, we use bismuth oxybromide for photocatalysis nitrogen reduction reaction, choosing solvothermal method to synthesize bismuth oxybromide, it providing simple, fast and high yield way in synthesis. Nitrogen reduction reaction is conducted in water without hole scavenger, and we use solar simulator as light source. In result, pristine bismuth oxybromide yield rate is 2.5 μmol hr-1 g-1. In order to enhance efficiency, the material is doped with iron atom and characterized by EDX、XRD、EPR, which efficiency enhance to 5.5 μmol hr-1 g-1. To obtain better efficiency from iron-doped bismuth oxybromide, the material process nitrogen reduction reaction under external magnetic field. The yield rate we obtain reach up to 15 μmol hr-1 g-1, which enhance 7-8 fold than pristine bismuth oxybromide. As the result, magnetic field can enhance the efficiency of iron-doped bismuth oxybromide.

並列關鍵字

Bismuth oxyhalide ； Photocatalysis ； Nitrogen reduction reaction ； Spin-polarization

參考文獻

1. Qing, G.; Ghazfar, R.; Jackowski, S. T.; Habibzadeh, F.; Ashtiani, M. M.; Chen, C.-P.; Smith III, M. R.; Hamann, T. W., Recent advances and challenges of electrocatalytic N2 reduction to ammonia. Chemical Reviews 2020, 120 (12), 5437-5516.

2. Modak, J. M., Haber process for ammonia synthesis. Resonance 2002, 7 (9), 69-77.

3. Nazemi, M.; Panikkanvalappil, S. R.; El-Sayed, M. A., Enhancing the rate of electrochemical nitrogen reduction reaction for ammonia synthesis under ambient conditions using hollow gold nanocages. Nano Energy 2018, 49, 316-323.

4. Huang, R.; Li, X.; Gao, W.; Zhang, X.; Liang, S.; Luo, M., Recent advances in photocatalytic nitrogen fixation: from active sites to ammonia quantification methods. RSC Advances 2021, 11 (24), 14844-14861.

5. Medford, A. J.; Hatzell, M. C., Photon-Driven Nitrogen Fixation: Current Progress, Thermodynamic Considerations, and Future Outlook. ACS Catalysis 2017, 7 (4), 2624-2643.