| 摘要: | 本計畫擬製備電化學法還原二氧化碳以及甲酸氧化反應之奈米觸媒。在碳能源循環當中，若能將再生能源應用以捕捉CO2，將CO2還原以合成燃料，則此能源循環是以化學能為主的儲存方式，相較於其他的如電池、氫能，將有更高的能量密度以及容易應用於目前的建設與設備。本計畫擬系統性的開發CO2電化學還原的電極材料。計畫目標有三，第一年使用CO2還原之逆反應之一，甲酸氧化，做為材料之快篩選擇，主要使用電化學系統量測。第二年製備金基奈米觸媒，並建置氣相層析分析儀(gas chromatography, GC)，量測CO2還原反應之CO, CH4產率。第三年則製備鈀基奈米觸媒，並建置高解析液相層析分析儀(high performance liquid chromatography, HPLC)，分析產物甲酸。由文獻中可知，電極材料例如Pt, Pd, Au, Ag等貴重金屬之CO2還原法拉第效率受到其結構(合金或核殼)，形貌(顆粒大小，深寬比，殼的厚度)，支撐物(碳黑，碳管等)以及電解液影響。因此本計畫由材料面著手，並使用國家同步輻射中心X光吸收光譜術，了解觸媒原子結構及氧化價態，另一方面，也配合申請人在2017年執行之科學與技術人員國外短期研究計畫，與美國加州大學爾灣分校之臨場掃描穿隧電子顯微鏡合作，了解材料在加熱與氣氛之臨場形貌與結構變遷。可獲得設計高催化活性及高穩定度觸媒之重要資訊。 ;In this project, the preparation and application of highly effective nanocatalysts toward CO2 reduction and formic acid oxidation reactions will be investigated. In these carbon-based energy cycles, if energy from renewable energy can be used to synthesize fuels from captured CO2, the storage of these energy sources is chemical energy based with higher energy density and ease of use within existing infrastructures when compared with electricity in batteries or hydrogen energy. Therefore, we will explore the CO2 reduction catalysts systematically. In the first year, we will use the reverse reaction of CO2 reduction, formic acid oxidation reaction, to screen the catalysts and the electrochemical analyzer will be used. In the second year, the Au-based nanocatalysts will be prepared and gas chromatography will be constructed to analyze the gaseous product such as CO and CH4 during CO2 reduction. In the third year, the Pd-based nanocatalysts will be prepared and high performance liquid chromatography will be constructed to analyze the liquid product such as formic acid during CO2 reduction. It has been reported that the faradaic efficiency of electrode materials such as Pt, Pd, Au, and Ag for CO2 reduction is highly related to their structures (alloy or core/shell), morphology (size, aspect ratio, and thickness of the shell), supports (carbon black and carbon nanotubes) and electrolytes. We will combine the synthesis of materials with two advanced in-situ technologies, including X-ray absorption spectroscopy (XAS) and scanning transmission electron microscopy (STEM), to elucidate the electronic states, atomic arrangements, and morphological and structural evolution during heating under specific atmospheres. The in-situ XAS will be performed in National Synchrotron Radiation Research Center in Taiwan while the in-situ STEM will be conducted in Department of Chemical Engineering and Materials Science, University of California. The combination of experimental, spectroscopic and microscopic results will open new insights into the design of highly effective and stable catalysts toward CO2 electrochemical reduction. |
