The development of heterogeneous catalysts for converting abundant biomass feedstocks to higher value products is one of the most challenges these days. 2,5-dihydroxymethylfuran (DHMF) and 2,5-dihydroxymethyltetrahydrofuran (DHMTHF), synthesized from HMF hydrogenation, serve as crucial precursors in various applications. Non-noble metal catalysts are particularly attractive for this reaction, given their affordability and impressive catalytic efficiency. This work unveils the origin of the unique selectivity over Ni and Cu through mechanistic investigation using density functional theory (DFT), thermodynamic and kinetic analyses. The results emphasize that temperature and solvent play a crucial role in altering the energetic stabilities of intermediates, thereby influencing the energetic span (δG), turnover frequency (TOF), and selectivity of the reaction. The theoretical results align well with experimental observations. At 373.15 K, the highest TOF values over Ni and Cu are predicted in the HMF-to-DHMTHF path (1.79 × 10h) and the HMF-to-DHMF path (4.01 × 10h), respectively, in gas phase—under low dielectric constant ε condition. In contrast, the highest TOF value for Ni is observed in the HMF-to-DHMF path under implicit water condition (ε = 78.4) at 298.15 K. Competitive DHMF desorption and further hydrogenation influence the reaction’s selectivity. These insightful fundamental findings reveal key descriptors essential for designing new heterogeneous catalysts or enhancing existing ones, with the aim of potentially impacting biomass upgrading and other hydrogenation reactions.

中文翻译：

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通过机理见解揭示 5-羟甲基糠醛 (HMF) 非贵金属催化氢化的选择性


开发用于将丰富的生物质原料转化为更高价值产品的多相催化剂是当今最大的挑战之一。由 HMF 加氢合成的 2,5-二羟甲基呋喃 (DHMF) 和 2,5-二羟甲基四氢呋喃 (DHMTHF) 是各种应用中的重要前体。非贵金属催化剂对于该反应特别有吸引力，因为它们的经济性和令人印象深刻的催化效率。这项工作通过使用密度泛函理论 (DFT)、热力学和动力学分析进行机理研究，揭示了对 Ni 和 Cu 的独特选择性的起源。结果强调，温度和溶剂在改变中间体的能量稳定性方面起着至关重要的作用，从而影响能量跨度（δG）、周转频率（TOF）和反应的选择性。理论结果与实验观察结果非常吻合。在 373.15 K 时，预测 Ni 和 Cu 的最高 TOF 值分别在气相中的 HMF-to-DHMTHF 路径 (1.79 × 10h) 和 HMF-to-DHMF 路径 (4.01 × 10h) 中（在低介电常数下）常数 ε 条件。相比之下，在隐式水条件 (ε = 78.4) 下，在 298.15 K 下，在 HMF 到 DHMF 路径中观察到 Ni 的最高 TOF 值。竞争性 DHMF 解吸和进一步氢化会影响反应的选择性。这些富有洞察力的基本发现揭示了设计新型多相催化剂或增强现有催化剂所必需的关键描述符，其目的是潜在地影响生物质升级和其他加氢反应。