電化學二氧化碳還原反應在銅錫雙金屬奈米觸媒上的反應機制研究

Abstract

將溫室氣體二氧化碳，轉化為有價值化學燃料的電化學二氧化碳還原反應(CO2RR)，已被研究許久且被證實可以有效解決溫室效應與能源短缺等問題。本篇論文中以油胺油酸法合成了CuSn雙金屬奈米觸媒，用於CO2RR中來提升效能及選擇性，並藉由能量散射光譜儀(EDX)及X光繞射儀(XRD)進行觸媒鑑定、X光光電子光譜儀(XPS)及循環伏安法(CV)推測觸媒結構、電化學分析儀及氣象層析儀(GC)測定觸媒效能。透過調整前驅物比例，我們觀測到隨著Sn的比例上升，CO的選擇性呈現先高後低的趨勢，Cu24Sn1具有最高的CO選擇性，其法拉第效率在電位-0.7 V (vs RHE)下達78.83%，電流密度為1.37 mA/cm2；而CH4的選擇性則相反，呈現先低後高的趨勢，Cu1Sn2具有最高CH4選擇性，其法拉第效率在電位-0.7 V (vs RHE)下達88.88%，電流密度為0.86 mA/cm2。透過調整CuSn比例，可以對*CO中間體的吸附能產生影響，進而改變CO2RR的選擇性。

Electrochemical carbon dioxide reduction reaction (CO¬2RR), which converts the greenhouse gas CO2 into valuable chemical fuels, has been studied for extensively to effectively solve problems of green-house effect and energy shortages. In this study, we synthesized CuSn bimetallic nanocatalysts using Oleylamine-Oleic acid method to find the catalytic trends with varied Cu/Sn composition. The samples were characterized by several techniques, including EDX, XRD, XPS. The electrochemical performance was measured by CV and GC. Our results found that the catalytic performance is varied with the composition. With few Sn contents, the sample of Cu24Sn1 prefers CO2 to CO conversion and its best activity is 78.83% CO FE with current density of 1.37 mA/cm2 at -0.7 V (vs RHE). The selectivity alters to CH4 at higher Sn contents Cu1Sn2 shows the best activity of 88.88% CH4 FE with current density of 0.86 mA/cm2 at -0.7 V (vs RHE). By adjusting Cu/Sn composition, the adsorption energy of the *CO intermediate can be influenced, thereby altering the selectivity of CO2RR.