Catalytic activity of palladium nanoparticles immobilized on an amino-functionalized ceramic membrane support

Pd nanoparticles were immobilized on a tubular ceramic membrane support. The support surface was functionalized by N-(β-aminoethyl)-γ-aminopropyl trimethoxy silane (AAPTS), which contains two amino groups. The Pd-immobilized ceramic membrane support was characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma emission spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. Its catalytic properties were investigated by the liquid phase hydrogenation of p-nitrophenol to p-aminophenol. The Pd-immobilized ceramic membrane support was compared with the Pd nanoparticles immobilized on a similar support functionalized by γ-amino-propyltriethoxy silane (3-APTS), which contains one amino group. Higher catalytic activity and stability were observed for the AAPTS-functionalized support. AAPTS contains twice as many amino groups as 3-APTS, and consequently exhibited a stronger electron-donating effect toward Pd. The AAPTS-functionalized ceramic membrane support contained more immobilized Pd nanoparticles, which were bound more strongly. This led to a higher catalytic activity and stability.