Individual Ni atoms on reduced graphene oxide as efficient catalytic system for reduction of 4-nitrophenol

Abstract

The intelligent design of surface active sites and their manipulation on the atomic level is a new research paradigm both in surface science and in catalysis. In this study, we synthesize a composite material, comprising atomically dispersed nickel on reduced graphene oxide support (rGO/Ni), in a simple wet chemistry procedure. The as-prepared material is fully characterized by the set of experimental techniques, including TEM with atomic resolution. Nickel atoms uniformly cover the rGO surface, and do not coalesce into nanoparticles. Individual Ni atoms are situated on the oxidized domains of rGO, being strongly coordinated by remaining oxygen functionalities. The as-prepared rGO/Ni demonstrates extraordinary efficiency in catalyzing reduction of 4-nitrophenol. For the first time, the catalysis of this reaction was successfully demonstrated in a prototype of a continuous flow reactor. The excellent catalytic properties of rGO/Ni are explained by the high surface area of the catalyst particles and high lateral density of the active sites. The reaction can be considered as an example of a single-atom catalysis. The low cost of materials and ease of preparation in the environmentally friendly conditions, open the doors for potential usage of this catalyst in the real industrial processes.