近年來，二氧化碳（CO₂）排放所造成之全球暖化問題日益嚴重，如何將CO₂轉換為高附加價值燃料已成為重要研究課題。其中，二氧化碳還原反應（CO₂RR）可將CO₂轉換為甲烷（CH₄）等碳氫化合物，但其活化過程需克服較高能障，因此高效能催化劑之開發備受關注。高熵合金（High-Entropy Alloys, HEAs）因具備多元素協同效應與可調控電子結構等特性，被視為具潛力之CO₂RR催化材料。
本研究利用密度泛函理論（Density Functional Theory, DFT），探討高熵合金電負度分佈差異與CO₂RR催化活性之關聯性。研究選用NiCuPtIr、FeCrNiCu及CoCuFeNi三種含銅高熵合金，其電負度分佈標準差分別為0.20、0.11及0.03。首先以逆蒙地卡羅演算法建立FCC高熵合金模型，並建構(111)表面進行吸附與反應能量分析。針對CO₂還原生成CH₄過程中的關鍵中間體（*COOH、*CO、*CHO、*CH₂O、*OCH₃、O及OH）計算吸附能，建立反應能量圖並分析速率決定步驟（RDS）。此外，利用Bader電荷分析探討電子轉移行為與催化活性之關聯。
結果顯示，吸附能主要受吸附位點元素種類影響，而第一鄰近原子環境之影響較小。相較於純銅催化劑，三種高熵合金皆具有較低之RDS能障，展現較佳催化潛力。隨著電負度分佈標準差增加，*CO吸附能力增強，RDS能量差則降低。其中NiCuPtIr之電負度分佈標準差最高（0.20），具有最低RDS能量差（0.915eV），展現最佳催化活性；NiCuFeCr與NiCuFeCo之RDS能量差則分別為0.953eV及1.093 eV。Bader分析結果進一步證實，較大的電負度差異可促進電子重分布，強化中間體與表面之鍵結作用，進而提升催化效能。
本研究證實高熵合金之電負度分佈標準差、*CO,*CHO吸附能力與CO₂RR催化活性之間具有明顯關聯，顯示電負度分佈可作為高熵合金催化劑設計與篩選的重要變因。

The increasing emission of carbon dioxide (CO₂) has intensified global warming, making the conversion of CO₂ into value-added fuels a crucial research focus. Among various approaches, the carbon dioxide reduction reaction (CO₂RR), which can convert CO₂ into hydrocarbons such as methane CH4 has emerged as a promising technology. However, the high thermodynamic stability of CO₂ necessitates efficient catalysts to overcome the reaction's energy barrier. High-entropy alloys (HEAs) have attracted considerable attention as promising CO₂RR catalysts due to their multi-element synergistic effects and tunable electronic structures.
In this study, density functional theory (DFT) was employed to investigate the correlation between electronegativity distribution and the catalytic activity of HEAs toward CO₂RR. Three Cu-containing HEAs—NiCuPtIr, NiCuFeCr, and NiCuFeCo—with electronegativity distribution standard deviations of 0.20, 0.11, and 0.03, respectively, were investigated. Reverse Monte Carlo simulations were used to construct random FCC structures, followed by the generation of (111) slab models for adsorption energy calculations. The adsorption energies of key intermediates (*COOH, *CO, *CHO, *CH₂O, *OCH₃, *O, and *OH) were calculated to determine the reaction energy profile and the rate-determining step (RDS). Bader charge analysis was also performed to examine charge redistribution during the reaction.
The results show that adsorption energy is primarily determined by the specific substrate metal element directly at the adsorption site, whereas the influence of the first-nearest-neighbor environment is relatively limited. Compared with pure Cu, all three HEAs exhibit lower RDS energy barriers. As the standard deviation of the electronegativity distribution increases, *CO and *CHO adsorption strengthens and the RDS energy barrier decreases. Notably, NiCuPtIr exhibits the lowest RDS energy barrier (0.915 eV) and the highest catalytic activity. Bader charge analysis further confirms that larger electronegativity differences promote electronic redistribution, strengthen intermediate–surface interactions, and enhance CO₂RR performance. These findings suggest that the electronegativity distribution can serve as an effective descriptor for designing high-performance HEA catalysts.

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