降低二氧化碳排放已成為全球重要課題，並促使高效能碳捕捉材料的開發。在本研 究中，選擇二碲化鈦 (TiTe2) 作為二氧化碳捕捉之候選材料，主因其具備二維結構，擁 有高表面積與體積比，使其在碳捕捉應用中展現潛在優勢。本實驗先透過氬離子 (Ar+) 轟擊進行缺陷工程，並利用反射是高能電子繞射 (RHEED) 與X 光光電子能譜 (PES) 追 蹤缺陷的演化行為。缺陷濃度則依據PES 分析所得到之電子結構變化程度進行定義。接 著將具有不同缺陷濃度值表面暴露於近常壓二氧化碳環境中，以探討缺獻濃度與二氧化 碳作用之關聯性，並於近常壓條件下進行分析。CO2 的吸附行為與缺陷濃度呈現明顯關 聯；缺陷的存在可促進CO2 的活化並有利於產物生成。在C 1s 光譜中觀察到碳相關及 C-O 相關產物，並在O 1s 光譜中同時出現Ti-O 與C-O 訊號，這些特徵共同指向CO2 已 發生解離反應。整體而言，TiTe2 的反應性隨缺陷濃度增加而提升，並在最佳缺陷濃度達 到最大值；當缺陷過多時，則反而限制整體反應效率。此外，對與二氧化碳反應後的樣 品進行逐步升溫實驗，並結合質譜分析，對反應過程中潛在產生的氣象產物進行監測， 進一步探討其可能反應路徑，數據顯示，留存表面的產物會隨著溫度上升發生熱轉變。 同時RHEED 量測結果指出，在二氧化碳曝氣過程中樣品的表面結構並未產生明顯變化。 綜合而言，氬離子轟擊能有效在二碲化鈦表面制造可控缺陷，其制造的表面缺陷可有效 影響二碲化鈦對於二氧化碳的反應性。;Reducing CO2 emissions has become a critical global priority， motivating the development of effective CO2 capture materials. In this study， TiTe2 was chosen as a candidate material for CO2 capture because its two-dimensional (2D) nature provides a high surface to volume ratio， making it a promising material for carbon capture application. Defect-engineering was first conducted using Ar+ bombardment， and the resulting defect evolution was monitored by Reflection High Energy Electron Diffraction (RHEED) and synchrotron-based Photoelectron spectroscopy (PES). The defect concentration was then defined based on the degree of alteration of electronic structure derived from PES analysis. Subsequently， the surfaces with different defect concentrations were exposed to CO2 to investigate the relationship between the defect concentration and CO2 reaction under near-ambient conditions. A clear dependence of CO2 adsorption on the defect concentration is observed， where the defects promote CO2 activation and product formation. The presence of carbonaceous and C-O species features in C 1s spectrum， together with Ti-O and C-O species in O 1s spectrum indicates CO2 dissociation， and TiTe2 reactivity increases with the defect concentration up to an optimal level， beyond which excessive defects limit the overall reactivity. Further insights into possible reaction pathway were obtained from stepwise heating experiments on the samples exposed to CO2， supported by separate mass spectrometry measurements， revealing thermally activated transformation of surface reaction product. Moreover， RHEED measurements on the sample exposed to CO2 show no significant structural change upon exposure. In summary， Ar+ bombardment offers an effective approach for tuning the surface reactivity of TiTe2 toward CO2 dissociation; the surface defects play an important role in governing this behavior.
