Azo-Bridged Bimetallic Porphyrin Polymer-Derived Co-Ni@PNC-x Nanocomposites for Efficient Catalytic Direct Amination of Benzene

To address the current problems of low yield and poor selectivity in direct amination of benzene, the Co-Ni@PNC-x composite catalysts were prepared in this work by using the azo-bridged (−N═N−) metalloporphyrin polymer as the template. The experimental results showed that Co-Ni@PNC-500, which was acquired by heat treatment of the Co-TNPP:Ni-TNPP = 3:2 precursor at 500 °C, exhibited the highest benzene conversion (78.4%) and selectivity (99.6%) for aniline. The structure and composition were analyzed in detail by XRD, FT-IR, Raman spectroscopy, TG-DTA, nitrogen adsorption/desorption, SEM, HRTEM, HAADF-STEM, STEM-EDX mapping, and XPS. The dominant active sites of the catalyst are the clusters of the bimetallic oxides CoNiO2 and Co2O3. The porphyrin-like carbon–nitrogen skeleton not only contributes to the stabilization of the Co/Ni active site, making the catalyst almost unchanged after several cycles, but also further forms the Co–Nx structure, which generates synergistic catalysis with the clusters of CoNiO2 and Co2O3 atoms to significantly enhance the efficiency of the catalysis. This catalyst is the excellent catalyst for anilination reactions with high prospects for industrial applications.