Metallic CuNPs confined in hollow silicalite-1: excellent catalytic efficiency in p-nitrophenol reduction

Abstract

Copper nanoparticles (CuNPs) confined in hollow silicalite-1 powders were synthesized by a selective “desilication–recrystallization” method using tetraethlyorthosilicate (TEOS), tetrapropylammonium hydroxide (TPAOH) and cupric chloride (CuCl₂) as precursors. The synthesized product was characterized by XRD, Raman, XPS, FESEM, TEM and N₂ adsorption–desorption studies. The presence of CuNPs of size 10–40 nm in the hollow silicalite-1 was confirmed by TEM. The BET surface area of the powders was 247 m² g⁻¹ composed of micropores and mesopores. The prepared CuNPs confined in hollow silicalite-1 showed excellent catalytic performance for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with apparent rate constant and activity parameter values of 5.6 × 10⁻³ s⁻¹ and 44.09 s⁻¹ g⁻¹, respectively for 1 mg of catalyst.