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  • 學位論文

氧化釕金屬高效率催化劑在酸性中產氧的反應機制分析

The in-situ insight of amorphous RuOx(OH)y with extremely low overpotential and high stability for OER in acidic electrolyte

指導教授 : 陳浩銘
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摘要


水分解為近年來再生能源發展儲能設備中相當具潛力的一環,而陽極產氧的 低效率一直為此研究的瓶頸。在此研究中,我們合成了以鈣鈦礦結構為模板的氧 化釕 金屬為主的無晶面催化劑,此催化劑在 0.5M 硫酸中之每平方公分十毫安 電流密 度的過電位僅僅只有 146 毫伏,為目前全球最有效率的數據,即使電流 密度拉 高至一百也其過電位也只有 190 毫伏。除此之外,其可在每平方公分十 毫安電 流密度維持 100 小時的穩定性。在此研究中,我們推敲出另一個可能的 反應機制,其反應機制與目前主要認同的機制有著相當大的差異,現行主要被認 可的機制是藉由單一金屬活性位與溶液中的水進行反應後,形成氧氧氫鍵後將氧 氣脫附,而我們認為反應過程中需要兩個活性金屬位與溶液中的水進行反應後形 成氧氧鍵,接著脫附後離開表面。而在臨場實驗中,X 光吸收光譜可以觀察到其 結構中的金屬金屬鍵隨電壓升高而靠近,我們認為這是此反應機制活性高的關 鍵,在臨場拉曼實驗中,我們也觀察到反應起始店為有氧氧鍵的生成,更能佐證 我們的提出的機制。除此之外,在酸性溶液中的所產生的氫鍵也扮演很重要的角 色,不但能協助拉近氧氧之間的距離,使其形成氧氧鍵,而氫氣本身的脫附也能 穩定金屬活性位的價態,使其保持穩定。除此之外,此陽極催化劑也可在中性環 境擁有良好的活性,除了水分解外,也可做二氧化碳還原。

關鍵字

產氧催化劑

並列摘要


Water splitting is considered as a promising way to meet the alternative energy demand. However, the low efficiency of oxygen evolution reaction (OER) is a huge obstruct of this research. Here, an amorphous Ru-based catalyst (RuOx(OH)y) was produced by virtue of the nature of perovskite as template followed by cation substitution, with lowest overpotential (of 146 mV at 10 mA/cm2 and 190 mV at 100 mA/cm2) in 0.5 M H2SO4 and high stability (up to 100 h by apply 10mA/cm2 chronopotentiometry), which hold the current OER record in acid media. The in situ extended X-ray absorption fine structure (EXAFS) spectra proved the presence of more metal edge sites (di-μ-oxo) than corner sites (mono-μ-oxo) embedded in RuOx(OH)y. We proposed a structure with short Ru–Ru bond as an active site which is a key for the mechanism of O–O coupling path leading to low overpotential. The hydrogen bonding at the surface of RuOx(OH)y contributes to the longevity against the dissolution of Ru ion at the on-set potential. The cutting-edge OER catalyst in acid media positively achieves its practical application accompanied by hydrogen evolution reaction (HER). Also, the RuOx(OH)y has attractive performance in neutral conditions and thus is a potential candidate for the anode catalyst of CO2 reduction.

並列關鍵字

OER

參考文獻


1. Total primary energy supply (TPES) by source https://www.iea.org/data-and-statistics?country=WORLD fuel=Energy%20supply indicator=Total%20primary%20energy%20supply%20(TPES)%20by%20source (accessed Jun 18, 2020).
2. Shakun, J. D.; Clark, P. U.; He, F.; Marcott, S. A.; Mix, A. C.; Liu, Z.; ... Bard, E. Nature. 2012, 484(7392), 49-54.
3. Meinshausen, M.; Meinshausen, N.; Hare, W.; Raper, S. C.; Frieler, K.; Knutti, R.; ... Allen, M. R. Nature. 2009, 458(7242), 1158-1162.
4. Jenkinson, D. S.; Adams, D. E.; Wild, A. Nature. 1991, 351(6324), 304-306.
5. Chu, S.; Majumdar, A. Nature. 2012, 488(7411), 294-303.

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