Chemical synthesis of Zr-/Ce-/Sm-containing intermetallic compounds catalyzing NaBH4-assisted hydrogenation of 4-nitrophenol

Abstract

Zr-/Ce-/Sm-containing intermetallic compounds, specifically ZrZnNi₄, CeNi₅, CeAlNi₄, CeNi₄Si, Ce(NiSi)₂, SmNi₃, SmNi₄Si, and Sm(NiSi)₂, were synthesized by reducing the metal oxides using a CaH₂ reducing agent within molten LiCl. The resultant nanopowders exhibited high specific surface areas: ZrZnNi₄ (42.0 m² g⁻¹), CeAlNi₄ (66.9 m² g⁻¹), and Sm(NiSi)₂ (25.0 m² g⁻¹). They were subsequently tested for their effectiveness in the NaBH₄-assisted hydrogenation of 4-nitrophenol. When compared to the prepared catalysts, including a conventional CeO₂-supported Ni catalyst, ZrZnNi₄ demonstrated the highest catalytic activity. Based on experimental results and density functional theory calculations, it was proposed that enhanced performance could be attributed to the formation of electron-rich Ni species in ZrZnNi₄.