Construction of\nHierarchical Porous Carbon Support\nPd Nanoparticle for Efficient Pyridine Hydrogenation Catalysis

Pd-based catalysts are increasingly being used in pyridine\nhydrogenation.\nSuitable catalyst supports are crucial for catalytic activity. Herein,\nthree Pd-based catalysts loaded on microporous carbon (AC), mesoporous\ncarbon (MC), and micromesoporous carbon (MAC) were tested for pyridine\nhydrogenation. The influence of catalyst supports, their porosity\ncharacteristics, and reaction conditions on the catalytic performance\nwas investigated. The results show that Pd/MAC catalyst exhibits \noptimal catalytic activity, which can achieve 99% conversion of pyridine\nand 99% yield of piperidine under the conditions of balloon pressure\nand room temperature. Specifically, Pd/MAC has excellent catalytic\nactivity even after 5 cycles and shows high compatibility with various <i>N</i>-heterocycles with a high yield. The excellent catalytic\nperformance is attributed to its multistage pore structure and a high\nspecific surface area, which provide more defects for loading of active\nsites and accelerate the mass transfer rate, and the uniformly dispersed\nultrafine active palladium nanoparticles can also greatly enhance\nthe catalytic activity. This work provides a feasible research idea\nfor the preparation of hydrogenation catalysts for pyridine analogues.