Predominant Catalytic Performance of Nickel Nanoparticles Embedded into Nitrogen-Doped Carbon Quantum Dot-Based Nanosheets for the Nitroreduction of Halogenated Nitrobenzene

A novel structure of a porous carbon–metal composite was designed and constructed from nitrogen-doped carbon quantum dots (NCQDs) and Ni. NCQDs (3–5 nm) with rich surface groups adsorbed with Ni ions can assemble into a carbon flake structure (50–60 nm) via atomic bonding, in which Ni is effectively dispersed and separated by NCQDs. Thus, a porous carbon nanosheet uniformly inlaid with metal nanoparticle (Ni@NCQDs) was built by subsequent thermal treatment. As a robust catalyst, Ni@NCQDs can promote the nitroreduction of p-chloronitrobenzene to p-chloroaniline with high activity (100%) and selectivity (99.8%) at 4.28 times the reaction rate of commercial Raney Ni. The electron transfer between Ni nanoparticles and porous carbon nanosheets over the N–Ni interface is responsible for the excellent performance. Besides, the wide applicability of Ni@NCQDs for various nitroarenes suggests that Ni@NCQDs have a potential to replace industrial catalysts (noble metal and Raney Ni). These findings confirm that the NCQDs, as an excellent carbon material, demonstrates a promising prospect of application in improving the catalytic performance of Ni-based catalysts.