Simple borophosphate glasses for on-demand growth of self-supported copper nanoparticles in the reduction of 4-nitrophenol.

Herein, we demonstrate a single-step synthesis of simple copper-doped borophosphate glasses and their unusual use for catalytic reduction of nitro groups from the aromatic nitro compounds. The copper-doped glasses were evaluated as an affordable heterogeneous catalytic glass-based material for the reduction of 4-nitrophenol by sodium borohydride. The glass matrix acts as a host and support material for in situ self-growth of zero-valent copper (Cu) nanoparticles (NPs) on the glass surface. Thus, zero-valent CuNPs are produced in situ on the glass surface that is accomplished by the interaction of copper ions with hydride ions. Using an intrinsic reaction kinetic constant, we find a catalytic activity of 0.144 L s-1 g-1 for a glass-based catalyst doped with a non-noble metal, which is an order of magnitude higher when compared to the values observed elsewhere. Furthermore, the reuse of glass catalyst after six successive cycles demonstrates an outstanding performance compared to that of the parent material. A mathematical model based on the Langmuir-Hinshelwood mechanism related to an empirical growth rate of the zero-valent CuNPs was proposed to describe the kinetic of the 4-nitrophenol catalytic hydrogenation.