Zirconium Carboxy-Aminophosphonate Nanosheets Loaded with Nickel-Boride Nanoparticles as an Efficient and Recyclable Catalyst for Nitroarene and Alkene Hydrogenation.

Stabilized nickel-boride (Ni x B) nanoparticles immobilized on zirconium carboxy-aminophosphonate nanosheets (Ni@ZrPGly) were synthesized, fully characterized, and applied as efficient and recyclable catalysts for the selective catalytic hydrogenation of nitroarenes and alkenes under very mild reaction conditions. The nanocatalysts were obtained by ion exchange of the acidic protons of exfoliated ZrPGly with nickel ions, followed by reduction, resulting in a uniform dispersion of Ni x B nanoparticles on the lamellar surface. Among the samples prepared with varying nickel loadings, Ni@ZrPGly-1, which possessed the highest Ni content, showed the greatest activity and selectivity in the reduction of nitroarenes using NaBH4 as a hydrogen source in methanol at 30 °C. The catalyst exhibited excellent recyclability, maintaining its catalytic performance over at least five consecutive cycles with negligible Ni leaching. A comparison with the completely inorganic zirconium phosphate nanocatalyst, Ni@ZrP, highlights the importance of the glyphosine groups in the formation and stabilization of Ni-boride nanoparticles. Moreover, Ni@ZrPGly-1 efficiently catalyzed the hydrogenation of alkenes under similar conditions, demonstrating its versatility as a sustainable heterogeneous catalyst.