Molecular-based design and emerging applications of nanoporous carbon spheres

Over the past decade, considerable progress has been made in the synthesis and applications of nanoporous carbon spheres ranging in size from nanometres to micrometres. This Review presents the primary techniques for preparing nanoporous carbon spheres and the seminal research that has inspired their development, presented potential applications and uncovered future challenges. First we provide an overview of the synthesis techniques, including the Stöber method and those based on templating, self-assembly, emulsion and hydrothermal carbonization, with special emphasis on the design and functionalization of nanoporous carbon spheres at the molecular level. Next, we cover the key applications of these spheres, including adsorption, catalysis, separation, energy storage and biomedicine — all of which might benefit from the regular geometry, good liquidity, tunable porosity and controllable particle-size distribution offered by nanoporous carbon spheres. Finally, we present the current challenges and opportunities in the development and commercial applications of nanoporous carbon spheres

A synthetic strategy for carbon nanospheres impregnated with highly monodispersed metal nanoparticles

N-doped mesoporous carbon nanospheres (N-MCN@M) impregnated with uniformly dispersed noble-metal (Au, Pt, Rh, Ru, Ag, Pd and Ir) nanoparticles are rationally designed and synthesized for hydrogenation reactions. This facile and generally applicable synthetic strategy ensured confinement of the noble-metal nanoparticles within different carbon morphologies, including mesoporous spheres, hollow particles and core–shell particles. High loading of the noble-metal nanoparticles from 8 to 44% was accomplished by tuning the initial concentration of metal salts. Even at very high loadings (>40 wt%), a homogeneous dispersion of uniform metal nanoparticles throughout the carbon nanostructures was achieved. The proposed synthesis is also well suited for the fabrication of carbon spheres loaded with bimetallic nanoparticles (AuPt, AuRh and PtRh). Examination of these metal-loaded carbon particles as catalysts for the hydrogenation of benzaldehyde gave 100% selectivity toward carbonyl group at room and higher reaction temperatures. The outstanding performance of Au nanoparticles gave an unprecedented turn over frequency 2–4 times greater than those of Pt nanoparticles with the same size, loading and support