Cyclic extrusion synthesis of mesoporous carbon-supported metal catalysts for selective hydrogenation

The mesoporous carbon-supported metal catalysts are important materials in heterogeneous catalysis. From the standpoint of process intensification, the current synthesis methods still suffer from several issues, such as the excessive use of toxic solvents, the time-consuming self-assembly process, and the difficulty of continuous production. Herein, we report a solvent-free and continuous route to synthesize mesoporous carbon-supported metal catalysts. Interestingly, the use of cyclic extrusion could promote mixing, coordination, and assembly of catalyst precursors (tannin-metal salts-additives) by shearing and squeeze force. The as-made mesoporous carbon-supported nickel materials showed high surface areas (up to 512 m(2) g(-1)), narrow pore size distribution (similar to 10 nm), and good performance in the selective hydrogenation of nitrobenzene to aniline (Conv. > 99%; Sel. > 99%). In addition, the fluid property of catalyst precursors and the geometry of the twin-screw extrusion channel were studied, and the essence of this cyclic extrusion process is also discussed.