普魯士藍類似物與碳材複合材料應用於電催化產氧反應

Prussian Blue Analogue and Carbon Materials Composites for Electrocatalytic Oxygen Evolution Reaction

林吟真(Yin-Chen Lin)

指導教授 ： 何國川

國立臺灣大學/工學院/化學工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202001559

摘要

本論文旨在討論普魯士藍類似物與碳材之複合材料於電催化產氧反應此一能源領域之應用。依照不同的材料此論文被分成兩部分：利用氧氣電漿活化奈米碳管/普魯士藍類似物之複合材料於電催化產氧反應之應用(第三章)，及以石墨烯量子點/普魯士藍類似物之複合材料為高效能觸媒於電催化產氧反應之應用(第四章)。
在第三章中，本研究闡釋利用氧氣電漿活化奈米碳管/普魯士藍類似物並應用於電催化產氧反應。奈米碳管具有良好的導電度以及電化學穩定性，而普魯士藍類似物含有均勻分布的鎳與鐵金屬，在普魯士藍類似物長晶過程加入表面修飾過的奈米碳管可以合成出奈米碳管/普魯士藍類似物之新穎複合材料。氧氣電漿微小的熱效應以及高能化學反應可以用來活化金屬點同時防止普魯士藍類似物結構崩塌，奈米碳管也能被活化藉此提升整體電催化產氧反應之效率。得益於特殊的結構與化學組成，本研究所合成出的奈米碳管/普魯士藍類似物之複合材料擁有優異的產氧反應活性，達到10 mA cm-2只需279 mV的過電位，並且在鹼性溶液中保有100小時以上良好的操作穩定性。根據實驗結果顯示，我們可將此方法應用在不同的金屬有機骨架以提升整體導電度及維持高比表面積結構，設計更多複合材料並應用在各式各樣的電化學領域。
在第四章中，我們成功合成石墨烯量子點/普魯士藍類似物之複合材料並應用於電催化產氧反應。石墨烯量子點擁有良好的分散性、導電性、大量的活性點以及可調控的表面官能基。現今，僅有少數論文將其應用在電催化產氧反應。金屬離子可以吸附在修飾後的石墨烯量子點表面並開始普魯士藍類似物之長晶過程。在此章節中我們依然利用氧氣電漿來提升此複合材料之活性。本研究所合成出的石墨烯量子點/普魯士藍類似物之複合材料有良好的導電性、大量活性點以及位於石墨烯量子點與普魯士藍類似物介面之晶格錯位，因此擁有優異的產氧反應活性，達到10 mA cm-2只需259 mV的過電位，並且在鹼性溶液中保有100小時以上良好的操作穩定性。此實驗結果展示了有效的策略去製備其他高活性的產氧反應觸媒。
根據第三章與第四章的核心概念，普魯士藍類似物可與不同的碳材結合形成各式各樣的複合材料。本論文所提出的策略將有助於開發出在能源應用領域中高效率的電催化觸媒。

關鍵字

奈米碳管 ； 石墨烯量子點 ； 產氧反應 ； 氧氣電漿 ； 普魯士藍類似物

並列摘要

This thesis aims at the synthesis and characterization of Prussian blue analogue (PBA) and carbon materials composites for electrocatalytic oxygen evolution reaction (OER) in the field of energy application. The thesis is mainly divided into two parts, namely, oxygen plasma activation of carbon nanotubes-interconnected Prussian blue analogue for oxygen evolution reaction (Chapter 3) and graphene quantum dots embedded Prussian blue analogue as an efficient electrocatalyst for oxygen evolution reaction (Chapter 4).
In Chapter 3, it is demonstrated that bimetallic PBA is interconnected by carbon nanotubes (CNTs) and then go through oxygen plasma treatment for OER. The functionalized CNTs, possessing superior conductivity and reliable electrochemical stability, are added to the crystallization process of PBA, having homogeneously distributed Ni and Fe elements. Oxygen plasma treatment is proposed to activate the metal sites and avoid the collapse of the framework owing to the small thermal effect and high chemical reactivity. Moreover, CNTs can be activated to improve OER catalytic activity via oxygen plasma treatment as well. The composite (O-CNT/NiFe) has the merits of high electrical conductivity as well as large active sites due to the complete framework of PBA and the activated CNTs. The optimized O-CNT/NiFe shows remarkable electrocatalytic properties with a low overpotential of 279 mV, a small Tafel slope of 42.8 mV dec−1, and an outstanding long-term stability for at least 100 h in alkaline condition. These results suggest that the proposed approach can be applied to other MOF-based nanostructures for enhancing the poor conductivity and maintaining frameworks of the pertinent electrocatalysts, which are the promising candidates for various applications.
In Chapter 4, graphene quantum dots (GQDs) embedded PBA was successfully synthesized for the first time. GQDs possess good dispersibility, high electrical conductivity, abundant active sites and edge sites, and tunable functionalities. To date, there are only a few attempts to employ GQDs for OER. The functionalized GQDs provide binding sites to metal ions for crystallization of PBA. Oxygen plasma treatment is utilized again in this part to improve the electrocatalytic performance. The obtained hybrid material (O-GQD/NiFe) exhibits impressive OER performance with a low overpotential of 259 mV, a small Tafel slope of 52 mV dec-1, and robust stability for at least 100 h in alkaline condition, resulting from faster electron transport and larger defect sites as well as more lattice mismatch between GQDs and PBA. Hence, this study broadens the scope for preparing other highly OER-active electrocatalysts in the future.
Based on the core concept of Chapter 3 and Chapter 4, PBAs can combine with different carbon materials, and thus construct various kinds of hybrid materials. The approach proposed in this thesis can be useful in developing highly efficient electrocatalysts in the field of energy application.

並列關鍵字

Carbon nanotubes ； Graphene quantum dots ； Oxygen evolution reaction ； Oxygen plasma treatment ； Prussian blue analogues

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