Is a support always needed in heterogeneous catalysis mediated by metal nanoparticles? The case of metal-organic alloys NiGraf and rNiGraf

Is a support always needed in heterogeneous catalysis mediated by metal nanoparticles? To answer the question, this study investigates metal-organic alloys NiGraf and its reduced version rNiGraf and their sol-gel entrapped versions in the catalytic reduction of nitroaromatics under ultramild conditions. Both NiGraf and rNiGraf consisting of jamborite nanoparticles entrapping graphene oxide and graphene within the crystal lattice and the ORMOSIL-entrapped NiGraf and rNiGraf are able to selectively mediate nitroaromatics selective hydrogenation. The sol-gel entrapped catalysts, however, employed in consecutive reaction runs rapidly lose the initial excellent activity. These findings are important in the quest for catalytic materials that can selectively convert nitroaromatic compounds to amines under mild conditions viable for upscaling and practical uptake.