在日趨嚴重的氣候變遷背景下，二氧化碳(CO2)排放為其中備受關注的核心議題之一，除了探索減排路徑外，如何有效捕捉並利用CO2亦屬重要。電化學二氧化碳還原反應(CO2RR)是實現碳資源循環再利用之關鍵技術，其中甲酸因具備高能量密度與成熟的下游應用，被視為極具潛力的C1產物。然而。本研究以鉍(Bi)、鉛(Pb)、銅(Cu)、鋅(Zn)作為元素系統組成中熵氧化物觸媒，透過製程優化、導電網絡工程與組成調變之系統性研究，成功構築出兼具高選擇性與長期穩定性之電催化轉化甲酸之中熵觸媒。 研究結果顯示，控制煅燒條件為600 °C並延長持溫時間至6小時，能有效抑制晶粒過度長大與團聚，並在維持多金屬元素均勻分佈的前提下，獲得具顆粒狀結構。研究進一步引入導電碳黑，不僅提升了催化顆粒的分散性，更大幅放大電化學活性表面積(ECSA)並降低電荷轉移阻抗(EIS)，在放大電流密度的同時，仍舊維持對甲酸的高選擇性，顯著提升整體反應速率。在組成調變方面，透過元素加倍與缺Bi設計，結果顯示Bi為維持該多四元中熵系統甲酸選擇性與反應穩定性之關鍵組成元素，隨著Bi含量的增加顯著地提升反應性能。 最終實驗表明，採用 Bi 加倍並經上述最適煅燒條件(600°C/6 hr)煅燒之觸媒(Bi2PbCuZn)nO，在−1.1 V vs. RHE電位下進行連續30小時的恆電位測試，其甲酸法拉第效率(Faradaic Efficiency， FE)始終維持在91%以上，且總電流密度與LSV曲線於測試前後幾乎無衰退，展現出優異的操作穩定性。本研究初步證實中熵觸媒於CO2RR中具備應用潛力。;Against the backdrop of increasingly severe climate change， carbon dioxide (CO2) emissions have emerged as a critical issue of global concern. Beyond emission reduction， the effective capture and utilization of CO2 is of paramount importance. The electrochemical CO2 reduction reaction (CO2RR) represents a key technology for carbon resource recycling， and formic acid is considered a highly promising C1 product due to its high energy density and mature downstream applications. In this study， a quaternary medium-entropy oxide system comprising bismuth (Bi)， lead (Pb)， copper (Cu)， and zinc (Zn) was developed as an electrocatalytic platform for CO2 reduction to formic acid， exhibiting both high selectivity and long-term stability. Calcination at 600℃ with an extended 6-hour dwelling time effectively suppressed excessive grain growth and agglomeration， yielding an overlapping columnar structure while maintaining uniform elemental distribution. Introducing conductive carbon black further enhanced particle dispersion， expanded the electrochemical active surface area (ECSA)， and reduced charge transfer resistance， thereby accelerating the reaction rate while preserving formic acid selectivity. Compositional tuning via element-doubling and Bi-deficient designs demonstrated Bi to be the key constituent for maintaining formic acid selectivity and reaction stability; its absence led to a marked decline in both performance and selectivity. The optimized catalyst， Bi-doubled (Bi2PbCuZn)nO calcined at 600℃/6 hr， underwent a continuous 30-hour potentiostatic test at −1.1 V (vs. RHE)， maintaining a Faradaic efficiency (FE) for formic acid consistently above 91%， with negligible degradation in current density or LSV curves. This study preliminarily validates the application potential of medium-entropy catalysts in CO2RR.
