To Alloy or Not to Alloy? The Unexpected Power of Pd–Au Catalyst Physical Mixtures in Efficient HMF Oxidation to FDCA

作者：Yani Peng, Xin-yue Zhou, Xuzhao Liu, Min Hu, Boya Qiu, Yilai Jiao, Carmine D’Agostino, Jesús Esteban, Christopher M. A. Parlett, Xiaolei Fan · 发表于：ACS Catalysis · 年份：2025 · DOI：10.1021/acscatal.5c02908 · 被引用次数：15 · 研究领域：Catalytic Processes in Materials Science、Asymmetric Hydrogenation and Catalysis、Oxidative Organic Chemistry Reactions

Bimetallic palladium (Pd) and gold (Au) systems are active for promoting the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a key building block for producing polyethylene furanoate, a biobased polymer to substitute poly(ethylene terephthalate). Here, an FDCA yield of ∼99% was achieved over a physical mixture of 1.5 wt % Au/C and 1.5 wt % Pd/C (Pd/Au molar ratio of 5:1) under mild conditions (90 °C, 1 bar O 2 ), outperforming bimetallic core–shell Au@Pd/C (∼90% FDCA yield) or alloyed AuPd/C (∼73% FDCA yield) systems. To gain insights into the synergy between the two monometallic catalysts, a series of kinetic studies were conducted employing either HMF or its intermediates as substrates in catalytic oxidation systems over either Pd/C or Au/C. The results show distinct selectivity preference of the two catalysts: Pd/C favors the 2,5-diformylfuran pathway (DFF), while Au/C follows the 5-hydroxymethyl-2-furancarboxylic acid (HFCA) pathway, as well as the presence of base-induced Cannizzaro disproportionation (CD) reactions. The advantage of the physical mixture system is largely attributed to the synergy between the two metals, which promotes the DFF pathway (over the HFCA route) and suppresses CD reactions, facilitating a more rapid progression of the overall oxidation cascade process. Catalyst recycling studies reveal deactivation of the physical mixture system (FDCA yield dropped to 62% after 3 cycles), with detailed comparative cha...