Catalysis of the hydro-dechlorination of 4-chlorophenol by Pd(0)-modified MCM-48 mesoporous microspheres with an ultra-high surface area

Abstract

MCM-48 mesoporous microspheres (M48N) with a pore size of 3.77 nm, an ultra-high surface area of 1250.77 m² g⁻¹ and a super-large pore volume of 1.52 cm³ g⁻¹ were synthesized. The M48N microspheres were then modified with Pd, Pt and Ru nanoparticles using an incipient wetness impregnation technique. The modified M48N microspheres were investigated to determine their catalytic effect in the aqueous phase hydro-dechlorination (HDC) of 4-chlorophenol. The Pd–M48N, Pt–M48N and Ru–M48N catalysts were characterized by transmission electron microscopy, X-ray diffraction, nitrogen adsorption–desorption and X-ray photoelectron spectroscopy. The HDC experiments were performed using the fairly mild conditions of room temperature and an atmospheric pressure of H₂. Pd–M48N showed a higher catalytic performance than Pt–M48N and Ru–M48N and various other Pd-based catalysts. The high catalytic performance of Pd–M48N resulted from the ultra-high surface area, super-large pore volume and unique pore structure of the M48N, which improved the mass transfer and increased the rate of adsorption–desorption of the compounds. This method has potential applications in the treatment of industrial wastewaters contaminated with chlorinated organic compounds.