Green-synthesized silver nanoparticles decorated on ceria nanorods for room-temperature p-nitrophenol hydrogenation

In this study, silver nanoparticles (AgNPs) loaded on pre-formed CeO2 nanorods (Ag-Ce) were synthesized using Jasminum subtriplinerve Blume leaf extract as a reducing agent. The mesoporous structure of CeO2 was confirmed by the N2 adsorption/desorption study, indicating type ІV isotherms with an H3-type hysteresis loop. The high specific surface area of the Ag-Ce samples was discovered in the range of 74–80 m2/g with an average pore diameter of 23.2–23.4 Å, and a pore volume of 0.091–0.093 cm3/g (pure CeO2 of 72 m2/g, 23 Å, and 0.098 cm3/g, respectively). Silver nanoparticles with spherical shapes (5–10 nm in diameter) were well dispersed on the surface of CeO2 nanorods (100–200 nm in length and 20–30 nm in diameter), as shown by X-ray diffraction (XRD), Energy-dispersive X-ray (EDX) and high-resolution transmission electron microscopy (HR-TEM). Their catalytic reactivity was investigated in the hydrogenation of p-nitrophenol (p-NP) toward p-aminophenol (p-AP) using NaBH4 at room temperature, exhibiting better reactivity of the Ag-Ce samples than pure CeO2 nanorods. The 0.2Ag-Ce sample (0.2 wt.% Ag) showed the complete conversion of p-NP toward p-AP after 3 min using 0.2 g/L catalysts.