In situ mosaic strategy generated Co-based N-doped mesoporous carbon for highly selective hydrogenation of nitroaromatics

Abstract

The development of heterogeneous non-noble metal catalytic architectures that can realize the high selective and stable hydrogenation of nitroaromatics under mild conditions is a profound challenge in the catalysis community. Here we report a facile synthesis of highly nitrogen doped and uniformly embedded Co-based mesoporous carbon catalyst through a thermolysis and etching combined strategy, in which the commercial cobalt phthalocyanine and colloidal silica serve as precursor and hard template, respectively. The protocol allows for simultaneous optimization of porous features and cobalt nanoparticles of N-doped mesoporous carbon catalyst by fine-tuning thermolysis temperature. Among the as-prepared catalysts, Co@NMC-800 with lower dosage of cobalt exhibits outstanding catalytic activity and chemoselectivity for various nitroaromatics under mild condition (2.0mol% Co, 1.0MPa H2, 80°C, <150min), which is significantly superior to all the existing non-noble metal-based catalytic systems. Dynamic analysis further demonstrates the apparent activation energy of nitrobenzene hydrogenation is as low as 28.0kJ/mol, accounting for the higher hydrogenation reaction rate. In addition, the synergistic effect between the CoNx and Co NPs surface wrapped thin carbon layers plays a crucial role in providing the excellent selectivity for hydrogenation of vulnerable nitroaromatics via preferential adsorption of polar nitro group.