催化学报 ›› 2026, Vol. 86: 225-235.DOI: 10.1016/S1872-2067(26)65020-6

• 论文 • 上一篇    下一篇

Ni6(SR)12团簇电催化环己酮氧化制备己二酸

翟庆喜a, 田轶棋a, 王浩a, 唐诗思a, 原强a, 刘旭a,*(), 丁维平a, 田凡b,*(), 祝艳a,*()   

  1. a 南京大学化学化工学院, 介观化学教育部重点实验室, 江苏南京 210093
    b 武汉工程大学化学与环境工程学院, 湖北武汉 430205
  • 收稿日期:2025-11-07 接受日期:2025-11-28 出版日期:2026-07-05 发布日期:2026-06-12
  • 通讯作者: *电子信箱: xuliu@nju.edu.cn (刘旭),
    tf@wit.edu.cn (田凡),
    zhuyan@nju.edu.cn (祝艳).
  • 基金资助:
    国家自然科学基金(22125202);国家自然科学基金(92461312);国家自然科学基金(U24A20487);国家自然科学基金(92361201);中石化石油化工科学研究院有限公司

Molecular adaptability and reactivity in Ni6(SR)12-catalyzed adipic acid synthesis

Qingxi Zhaia, Yiqi Tiana, Hao Wanga, Shisi Tanga, Qiang Yuana, Xu Liua,*(), Weiping Dinga, Fan Tianb,*(), Yan Zhua,*()   

  1. a Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, Jiangsu, China
    b School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, China
  • Received:2025-11-07 Accepted:2025-11-28 Online:2026-07-05 Published:2026-06-12
  • Supported by:
    National Natural Science Foundation of China(22125202);National Natural Science Foundation of China(92461312);National Natural Science Foundation of China(U24A20487);National Natural Science Foundation of China(92361201);SINOPEC Research Institute of Petroleum Processing Co., Ltd.

摘要:

己二酸是一种重要的化工中间体, 广泛应用于尼龙-66、聚氨酯和食品添加剂等化学品的生产. 目前, 工业上约95%的己二酸通过热催化反应制备, 该过程涉及KA油(环己酮和环己醇)在50%-65%硝酸中的氧化, 产生大量一氧化二氮温室气体. 电催化氧化为己二酸的绿色合成提供了理想途径. 本文利用原子级精确金属团簇作为模型催化剂, 旨在原子水平阐明金属核与配体环境协同调控催化性能的机制.

本研究报道了两种应用于电催化环己酮氧化制备己二酸的原子精确团簇催化剂, 分别为苯乙硫醇配体保护的Ni6(SC2H4Ph)12和正十二烷硫醇配体保护的Ni6(SC12H25)12团簇. 这两种团簇具有相似的金属核, 但它们不同的表面配体外部环境能够调控水分子和环己酮分子到金属核的可及性, 从而显著影响催化活性和选择性. 在纯KOH电解液中, 在电流密度为10 mA cm-2时, 与Ni6(SC2H4Ph)12团簇相比, Ni6(SC12H25)12团簇具有较低的过电势(350 mV), 表明Ni6(SC12H25)12团簇更有利于析氧反应. 相反, 在含有环己酮分子的KOH电解液中, Ni6(SC2H4Ph)12催化剂具有更优异的己二酸法拉第效率和收率. 在1.52 V vs. RHE时, Ni6(SC2H4Ph)12催化剂可达89.3%的己二酸法拉第效率. 分子动力学模拟和时间分辨原位傅里叶变换红外光谱研究表明, 水分子优先吸附在Ni6(SC12H25)12团簇金属核上, 进而阻碍了环己酮分子接近金属镍活性中心, 导致Ni6(SC12H25)12团簇更容易发生析氧反应; Ni6(SC2H4Ph)12团簇中的苯乙硫醇配体使环己酮的C=O基团更容易接近, 并吸附在金属镍位点并活化转化, 同时, 苯乙硫醇与Ni核之间较强的电子相互作用促进环己酮氧化反应, 实现较高的己二酸法拉第效率和产率. 电化学原位红外光谱和中间体氧化实验证明了2-羟基环己酮和6-羟基己酸为该反应的关键中间体. 密度泛函理论计算结果表明, 与Ni6(SC12H25)12相比, Ni6(SC2H4Ph)12催化剂对于反应决速步骤(*C6H10O3到*C6H9O3)具有较小的反应能垒(1.38 eV), 更有利于己二酸的生成, 进一步揭示了催化剂周围环境对环己酮电化学氧化路径的影响.

综上, 本研究利用原子级精确金属团簇催化剂金属镍核与有机配体协同互补机制, 调控反应物到活性位点的可及性, 实现了高效环己酮氧化转化制己二酸, 为精准构筑多相催化活性位点、调控反应物可及性与催化选择性提供了全新策略.

关键词: 电催化氧化, 环己酮, 己二酸, 分子自适应, 精确团簇

Abstract:

Constructing the active sites of a heterogeneous catalyst, controlling the accessibility of molecules to active sites and ultimately tailoring its catalytic property are of utmost significance yet highly challenging. Herein, we report two systems of atomically precise cluster catalysts for the cyclohexanone electrooxidation reaction, which correspond to 2-phenylethanethiol-protected Ni6(SC2H4Ph)12 and 1-dodecanethiol-protected Ni6(SC12H25)12. The two clusters are identified to have similar metal active cores while their distinct surrounding environments access to the metal cores are capable of discriminating between water and cyclohexanone, exhibiting substantially influences on their activity and selectivity. Our studies reveal that water molecules are preferably adsorbed onto the surface of the Ni6(SC12H25)12, thereby pushing the cyclohexanone molecule away from the metal core, which favors the oxygen evolution reaction on the Ni6(SC12H25)12 catalyst. In contrast, the cyclohexanone is adaptively pulled toward the Ni core by the 2-phenylethanethiol ligands of Ni6(SC2H4Ph)12, in which the C=O group of the cyclohexanone can approach, adsorb and convert over the Ni sites and 2-phenylethanethiol ligands have stronger electron interactions with Ni core facilitating the cyclohexanone oxidation reaction on the Ni6(SC2H4Ph)12 catalyst and hence achieving high faradaic efficiency and high yield for adipic acid. This study challenges the conventional heterogeneous catalysts without atomic-precision structure and instead couples the complementary roles of the inner and outer environments of the cluster catalysts to tailor their catalytic properties.

Key words: Electrooxidation, Cyclohexanone, Adipic acid, Molecular adaptability, Clusters