Ru@Carbon Nanotube Composite Microsponge: Fabrication in Supercritical CO(2) for Hydrogenation of p-Chloronitrobenzene

Novel heterogeneous catalysts are needed to selectively anchor metal nanoparticles (NPs) into the internal space of carbon nanotubes (CNTs). Here, supercritical CO(2) (SC-CO(2)) was used to fabricate the Ru@CNT composite microsponge via impregnation. Under SC-CO(2) conditions, the highly dispersive Ru NPs, with a uniform diameter of 3 nm, were anchored exclusively into the internal space of CNTs. The CNTs are assembled into a microsponge composite. The supercritical temperature for catalyst preparation, catalytic hydrogenation temperature, and time all have a significant impact on the catalytic activity of Ru@CNTs. The best catalytic activity was obtained at 100 °C and 8.0 MPa: this gave excellent selectivity in the hydrogenation of p-chloronitrobenzene at 100 °C. This assembly strategy assisted by SC-CO(2) will be promising for the fabrication of advanced carbon composite powder materials.