含吡唑雙亞硝基鐵錯合物電催化還原水及二氧化碳之研究

Study on electrocatalytic reduction of H2O and CO2 using pyrazolate－containing DNIC

林靜瑜(Jing-Yu Lin)

指導教授 ： 魯才德

中原大學/理學院/化學研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600340

摘要

近年來為了解決能源短缺，以及石化燃料造成嚴重溫室效應，因此如何減少大氣中CO2的含量，與開發新替代能源成為重要的議題，新能源又希望以環保，不產生溫室氣體為首要，而氫能源就是一個很好的研究方向，因為氫氣燃燒後生成水，水又可進一步還原成氫氣，對環境不會有嚴重影響。而CO2除了從源頭管制之外，也可用化學的方式，將其還原成具有經濟效益的碳氫化合物。
因此本研究成功的利用吡唑(pyrazole)做為配位體，合成出一系列的雙亞硝基鐵錯合物{Fe(NO)2}9-{Fe(NO)2}9，[(NO)2Fe(-RPyr)2Fe(NO)2] (1-Me，R = Me；1-NH2，R = NH2)。並將這種具有兩個電子氧化還特性的錯合物，嘗試是否能作為催化劑，催化水還原成氫氣與能否對CO2進行電催化還原反應。
分別探討在水相中，電解水還原成氫氣的起始電壓和電流密度的變化，和氫氣生成的轉換效率，以及水相與有機相下，能否與CO2有電化學反應，並對其產物進行進一步的探討。發現在水相下，1-NH2可以有效的降低還原水的起始電位至-1.40 V(vs. SCE)，長時間在水相下也有良好的穩定性，且法拉第效率也達到100 %。此外在甲醇環境下，1-Me和1-NH2也能夠與CO2進行電化學反應，雖然電解過程中約80 %的電子，都用在電解甲醇生成氫氣上，但我們仍成功的將CO2還原成甲酸根，而其轉換效率低是未來需要克服的問題。

關鍵字

雙亞硝基鐵錯合物 ； 電催化

並列摘要

For the past few years, untilization of fossil fuel as main energy source caused the serious greenhouse effect. Scientists attempted to develop an alternative energy source to solve the problem and reduce the CO2 emission. In this work, we successfully synthesized dinuclear DNICs containing pyrazolate bridging ligands [(NO)2Fe(μ-RPyr)2Fe(NO)2] (Pyr = pyrazolate, R = Me, NH2). These complexes show two electron reversible redox interconversion between {Fe(NO)2}9-{Fe(NO)2}9, {Fe(NO)2}9-{Fe(NO)2}10 and {Fe(NO)2}10-{Fe(NO)2}10. We try as whether catalytic reduction of water into hydrogen and electrocatalytic reduction with CO2.
In the aqueous phase, our complexes have lower onset potential of electrocatalytic reduction of water -1.40 V(vs. SCE) and good stability in the prolonged electrolysis, and the Faraday efficiency of hydrogen generation reaches 100%. However, 1-Me and 1-NH2 can electrochemical react with CO2 in methanol, although about 80% of the electrons used in generating hydrogen when the process of electrolysis, we succeed reduce CO2 to formic, and the low conversion efficiency is the problem to be overcome in the future.

並列關鍵字

electrocatalytic reduction ； pyrazolate－containing DNIC

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