A supported cobalt catalyst with atomically dispersed Co-N_x sites (3.5 wt% Co) in a mesoporous N-doped carbon matrix (named [email protected]) is synthesized by hydrolysis of tetramethyl orthosilicate (TMOS) in a Zn/Co bimetallic zeolitic imidazolate framework (BIMZIF(Co,Zn)), followed by high-temperature pyrolysis and SiO₂ leaching. A combination of TEM, XRD XPS and X-ray absorption spectroscopy studies confirm the absence of cobalt nanoparticles and indicate that these highly dispersed cobalt species are present in the form of Co-N_x. The exclusive formation of Co-N_x sites in the carbon matrix is attributed to the presence of a large amount of Zn and N in the BIMZIF precursor together with the presence of SiO₂ in the pore space of this framework, extending the initial spatial distance between cobalt atoms and thereby impeding their agglomeration. The presence of SiO₂ during high-temperature pyrolysis is proven crucial to create mesoporosity and a high BET area and pore volume in the N-doped carbon support (1780 m² g⁻¹, 1.54 cm³ g⁻¹). This heterogeneous [email protected] catalyst displays high activity and selectivity (>99%) for the selective hydrogenation of nitrobenzene to aniline at mild conditions (0.5–3 MPa, 343–383 K). When more challenging substrates (functionalized nitroarenes) are hydrogenated, the catalyst [email protected] displays an excellent chemoselectivity to the corresponding substituted anilines. The presence of mesoporosity improves mass transport of reactants and/or products and the accessibility of the active Co-N_x sites, and greatly reduces deactivation due to fouling.

通过在Zn / Co双金属沸石中水解原硅酸四甲酯（TMOS）合成在介孔N掺杂碳基质（命名为[email protected]）中具有原子分散的Co-N _x位点（3.5 wt％Co）的负载型钴催化剂。咪唑酯骨架（BIMZIF（Co，Zn）），然后进行高温热解和SiO ₂浸出。TEM，XRD XPS和X射线吸收光谱研究的结合证实了钴纳米颗粒的不存在，并表明这些高度分散的钴物种以Co-N _x的形式存在。碳基质中Co-N _x位点的排他性归因于BIMZIF前体中大量Zn和N的存在以及SiO ₂的存在在该骨架的孔隙空间中，钴原子之间的初始空间距离延长，从而阻碍了它们的团聚。的SiO存在₂高温热解过程中被证明关键以在n型掺杂的碳载体孔性和高的BET表面积和孔体积（1780米²克^-1，1.54厘米³克^-1）。这种多相[受电子邮件保护的]催化剂在温和条件下（0.5-3 MPa，343-383 K）对硝基苯选择性加氢成苯胺显示出高活性和选择性（> 99％）。当更具挑战性的底物（官能化的硝基芳烃）被氢化时，催化剂（受电子邮件保护）对相应的取代苯胺显示出优异的化学选择性。中孔的存在改善了反应物和/或产物的质量传递和活性Co-N _x位点的可及性，并大大减少了由于结垢而引起的失活。