A reduced NiGraf metal organic alloy in the hydrogenation of nitrobenzene to aniline: a computational analysis

Consisting of graphene oxide molecularly entrapped within jamborite nanoparticles, NiGraf (GO@Ni) is a versatile electrocatalyst for both hydrogen and oxygen evolution reactions involved in water electrolysis. Its reduced form obtained via reduction of jamborite-entrapped GO with thiophene (RGO@Ni) is a highly active and stable hydrogenation catalyst enabling the reduction of nitrobenzene to aniline at 35 °C in the liquid phase using water as an “on-solvent” reaction medium under biphasic conditions. Besides eliminating the need for an organic solvent, the process has significant practical application potential for the synthesis of a compound produced worldwide at a rate of 7 million tonnes per annum. Here we report the outcomes of a DFT computational study aimed at investigating the catalytic activity and stability of the reduced form of NiGraf in mediating the nitrobenzene hydrogenation to aniline. Results based on calculating the adsorption energies of the two reactant substrates and analyzing the corresponding adsorption modes support a reaction mechanism that explains also the catalyst's remarkable stability.