Dual-metal synergy unlocking ROS-free catalysis for rapid aerobic oxidation of 5-hydroxymethylfurfural at room temperature  

双金属协同催化非ROS介导的5-羟甲基糠醛选择氧化

作　　者：Meiyun Zhang Penghua Che Hong Ma Xin Liu Shujing Zhang Yang Luo Jie Xu 张美云;车鹏华;马红;刘鑫;张树静;罗杨;徐杰(中国科学院大连化学物理研究所,大连洁净能源国家实验室,能源催化转化全国重点实验室,辽宁大连116023;中国科学院大学,北京100049)

机构地区：[1]State Key Laboratory of Catalysis,Dalian National Laboratory for Clean Energy,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Journal of Catalysis》2024年第12期144-156,共13页催化学报(英文)

基　　金：国家重点研发计划(2022YFA1504902);国家自然科学基金(22272172,22072149,21790331).

摘　　要：Clean catalytic oxidation has a broad prospect in the modern chemical engineering and energy chemistry fields.However,unexpected over-oxidation and disruptive degradation are frequently induced by excessive reactive oxygen species(ROS).Herein,we reported a new ROS-free approach to effectively drive O_(2) to be activated into highly reactive surface peroxo species through enzyme-mimicking mechanism.Benefiting from the dual-metal synergy effect between Cu and Co active sites,ROS(H_(2)O_(2) and OH•)is generated in situ while further scavenged completely into surface peroxo species,which gives rise to very high selectivity and extremely high carbon balance.For example,the CuCo/N-C catalyst affords>99.8%conversion and 94.5%selectivity to 2,5-furanedicarboxylic acid at 25℃ for 6 h in the aerobic oxidation of biomass platform 5-hydroxymethylfurfural.Moreover,it achieved exceptional performance in the oxidation of a variety of hydroxyl compounds to organic acids with high yields(89.9%–99.5%)at a mild temperature(25–40℃).This exploration introduces an innovative clue for emulating enzyme catalysts,thereby enriching our comprehension and advancement of biologically inspired catalytic oxidations.分子氧清洁催化氧化制备有机含氧化学品,在现代化工和能源化学领域具有重要的研究和应用意义.在生物质资源化利用中,5-羟甲基糠醛(HMF)氧化制备可再生聚酯单体2,5-呋喃二甲酸近年备受关注,有望缓解石油基聚对苯二甲酸乙二醇酯广泛使用所带来的环境问题.然而,分子氧活化过程常伴随活性氧物种(ROS)的形成,ROS的复杂性质和难控制性,会导致产物选择性低、氧化降解以及低碳平衡等问题.因此,探索特定活性氧物种的产生与清除机制,减少ROS的负面影响,仍然是实现高效高选择性氧化技术的关键挑战.受到天然酶具有活化分子氧及清除ROS的双重性能启发,本文报道了一种非ROS介导催化氧化的新方法,研制出CuCo/N-C双金属纳米催化剂,通过双金属协同效应在室温下将O_(2)活化成高活性表面过氧物种,完全清除了体系中游离的ROS,从而在温和条件下(25–40℃)以高产率(89.9%–99.5%)将多种羟基化合物催化氧化为相应的有机羧酸.使用CuCo/N-C催化剂在25℃和1 MPa O_(2)下反应6 h,生物质平台分子HMF的转化率>99.8%,2,5-呋喃二甲酸的选择性达到94.5%.球差校正高角度环形暗场扫描透射电子显微镜等表征表明,Co-N位点和小尺寸Cu2O位点在氮掺杂碳材料表面高度分散.自由基捕获-电子顺磁共振波谱和紫外-可见光谱与气相色谱-质谱联用等测试结果表明,CuCo双金属在分子氧室温活化中发挥了协同效应.在水相体系中,Co-N活性位点通过表面富电子特性原位活化O_(2)生成H_(2)O_(2),Cu2O位点在碱性条件下进一步完全清除原位产生的H_(2)O_(2)及其分解的OH•自由基,生成高活性的表面过氧化铜物种,从而获得了高的选择性和碳平衡.动力学同位素效应研究结果表明,CuCo/N-C获得了6.7的高KIE值(kH(PhCH_(2)OH)/kD(PhCD2OH)),说明C–H键的H脱除为反应的速控步骤,这可能与表面过氧化铜物种的形成有关.综上,本研究提�

关 键 词：Biomass Dual metal synergy Molecular oxygen activation 5-HYDROXYMETHYLFURFURAL Reactive oxygen species free Selective oxidation 

分 类 号：O64[理学—物理化学]