催化学报

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界面双位点协同增效近中性介质中的生物质电氧化反应

卜辰宇a,1, 卢卓然a,1, 夏忠诚a,1, 黄裕呈d, 樊赟a, 王才荣a, 黄雨桐a, 王双印a, 邹雨芹a,b,c*   

  1. a湖南大学化学化工学院, 教育部能源电化学国际联合实验室, 化学生物传感全国重点实验室, 湖南长沙 410082;
    b湖南大学重庆研究院, 重庆 401120;
    c湖南大学大湾区创新研究院, 广东广州 511340
  • 收稿日期:2025-09-11 接受日期:2025-09-11
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家重点研发计划(2023YFA1507400); 国家自然科学基金(U24A20498); 重庆市自然科学基金(CSTB2022NSCQ-MSX0354); 广东省基础与应用基础研究基金(2024A1515012702).

Interfacial two-site synergy for biomass electro-oxidation in a near-neutral electrolyte

Bu Chenyua,1, Lu Zhuorana,1, Xia Zhongchenga,1, Lu Ying Ruid, Fan Yuna, Wang Caironga, Huang Yutonga, Wang Shuangyina, Zou Yuqina,b,c*   

  1. aState Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, International Joint Lab of Energy Electrochemistry of the Ministry of Education, Hunan University, Changsha 410082, Hunan, China;
    bResearch Institute of Hunan University in Chongqing, Chongqing 401120, China;
    cGreater Bay Area Institute for Innovation of Hunan University, Hunan University, Guangzhou 511340, Guangdong, China
  • Received:2025-09-11 Accepted:2025-09-11
  • About author:1Contributed equally to this work.
  • Supported by:
    National Key R&D Program of China (2023YFA1507400), the National Natural Science Foundation of China (U24A20498), the Provincial Natural Science Foundation of Chongqing (CSTB2022NSCQ-MSX0354), and the Guangdong Basic and Applied Basic Research Foundation (2024A1515012702).

摘要: 生物质电氧化作为一种新兴的产物增值策略,因其能耗低、操作条件环保等优势而备受关注.5-羟甲基糠醛(HMF)作为关键生物质平台分子,可被氧化生成2,5-呋喃二甲酸(FDCA),该产物被视为聚合物工业生产中对苯二甲酸的替代品.然而,当前HMF电氧化反应(HMFOR)在碱性电解质中面临副反应多(HMF自聚合和腐殖质形成)、设备腐蚀严重等问题.相较之下,近中性电解质下的HMFOR能够抑制底物降解并保持催化剂结构稳定性,为持续合成高纯度FDCA提供了可行方案.但近中性电解质存在的困难主要在于活性氧物种的不足、氧化反应往往停留在中间阶段,无法高效生成FDCA.因此,通过对催化剂界面位点进行理性设计与精准调控,是实现高收率的FDCA合成的关键.
本文设计了原子级分散钌负载氧化铜(Ru/CuO)电催化剂,利用Ru组分促进近中性体系下OH-的原位生成,协同CuO优异的有机物电氧化性能,高效实现了HMF向FDCA的完全转化.高角度环形暗场扫描透射电子显微镜、X-射线光电子能谱及X-射线吸收光谱表明,Ru/CuO催化剂中Ru以单原子形式均匀、稳定锚定在CuO载体表面,且两组分间存在较强的电子耦合作用.电解实验表明,在较低电位1.15 VRHE时,Ru/CuO即实现了93%的FDCA产率和87.7%的法拉第效率,并在较宽的电势范围内(1.15-1.35 VRHE)均可以实现80%以上的FDCA产率.进一步组装流动电解池进行实验放大和稳定性测试,结果表明,该体系可以保持稳定电解200 h,且在整个循环过程中,Ru/CuO始终保持近100%的HMF转化和高于85%的FDCA选择性.通过过程取样及原位傅里叶变换红外光谱(FT-IR)对反映中间体进行了监测,明确了羟基优先氧化的反应路径.对Ru/CuO的增强机制进行进一步探究,原位FT-IR及循环伏安测试有力证实了Ru组分的水解能力,通过实现原位OH-的生成,高效提升催化界面的局域碱度; 此外,Ru/CuO的活性与HMF和OH-的浓度比呈现火山型关系,这表明Ru/CuO遵循直接氧化机制,这可能是实现低电位下HMF完全氧化生成FDCA的关键.借助石英晶体微天平测试定量比较了Ru/CuO与单组分CuO的有机物吸附能力; 结果表明,Ru/CuO更有利于底物分子HMF在界面的富集(650 ng vs. 108 ng).理论计算结果表明,相较于CuO,Ru/CuO展示出更低的水解离能和HMF吸附能.对HMFOR反应全路径分析发现,CuO催化反应时速率决定步骤为5-甲酰基-2-呋喃甲酸的初始脱氢,吉布斯自由能为1.07 eV,而Ru的引入成功将该能垒降低至0.01 eV,使该脱氢过程在热力学上更易实现.
综上,本文开发了一种高效催化剂实现了近中性条件下HMF向FDCA的深度转化,并通过多项表征与理论计算揭示了Ru与CuO界面协同催化机制,从而确立了界面工程作为破解生物质增值过程中能量势垒的关键策略.

关键词: 5-羟甲基糠醛, 近中性电解质, 电催化, 电氧化, 2,5-呋喃二甲酸

Abstract: Electrocatalytic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) in a near-neutral electrolyte mitigates HMF polymerization, thereby enhancing catalyst stability for long-term operation. However, the insufficient supply of active oxygen species during the electro-oxidation process often leads to the formation of partially oxidized intermediates instead of the desired product, 2,5-furandicarboxylic acid (FDCA). In this study, an atomically dispersed ruthenium-loaded copper oxide electrocatalyst (Ru/CuO) is prepared to promote the generation of hydroxide (OH-) ions and facilitate complete HMF oxidation to FDCA. In-situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy, density functional theory calculations, and quartz crystal microbalance mass analysis revealed that CuO serves as the active site for the HMF oxidation reaction (HMFOR), whereas the introduction of Ru single atoms accelerates OH- formation, lowers the reaction barrier for the key dehydrogenation steps in HMFOR, and enhances HMF adsorption. These features enable the Ru/CuO catalyst to deliver significantly improved low-potential oxidation performance under near-neutral conditions, reaching a 93% FDCA yield and 87.7% Faradaic efficiency at 1.15 VRHE, along with stable operation in a flow cell. This work demonstrates efficient conversion of HMF to FDCA in a near-neutral electrolyte and proposes a rational design strategy for HMFOR catalyst operating under near-neutral conditions.

Key words: 5-Hydroxymethylfurfural, Near-neutral electrolyte, Electrocatalysis, Electro-oxidation, 2,5-Furandicarboxylic acid