Development of novel monolithic catalyst with porous hollow silica nanoparticles for selective hydrogenation reactions

• Monolithic catalysts prepared by coating porous hollow nano-catalysts on substrate.
• The new catalyst kept the excellent catalytic performance from the nano-washcoat.
• The new catalyst showed high selectivity for selective hydrogenation of acetylene.
• Adding a proper amount of Ag further enhanced the catalytic performance.

Novel monolithic catalysts were prepared with Pd nano-catalysts on porous hollow silica nanoparticles (PHSNs, the supporting active sites) as washcoat and monolithic cordierite (MC) as the monolithic ceramic substrate. The coating of PHSNs could increase the surface area of MC for more than 10 times and also endue the coated layer with engineered porous hollow structure; therefore, the new monolithic catalysts were expected to keep both the excellent catalytic performance from the nano-washcoat and the fine mechanical properties from the monolithic substrate. The obtained samples were characterized with Scanning Electronic Microscope (SEM), ultrasonic vibration test and X-Ray Diffraction (XRD). SEM images showed that the monolithic catalysts were covered with a PdO/PHSNs washcoat of ∼10 μm thickness. Ultrasonic vibration tests indicated that the washcoat was anchored on monolithic substrates firmly. And XRD results demonstrated that the coating layers maintained the mesoporous hollow structure of PHSNs after being coated on MC. Finally, the catalytic properties of the novel Pd-loaded monolithic catalysts were determined by selective hydrogenation of acetylene in excessive ethylene, which showed that the selectivity of Pd-loaded PHSNs-Al2O3/MC catalysts was higher than other Pd supported catalysts, and adding a proper amount of Ag to PdO/PHSNs-Al2O3/MC catalysts could further enhance the catalytic performance.

In this work, novel monolithic catalysts were prepared by coating porous hollow nano-catalysts on monolithic cordierite substrates to keep both the excellent catalytic performance from the nano-washcoat and the fine mechanical properties from the substrate. Enhanced catalytic performance of the new monolithic catalysts was demonstrated for selective hydrogenation of acetylene. It also offered a new route for more efficient utilization of the quick-developing nano-catalysts.Figure optionsDownload high-quality image (313 K)Download as PowerPoint slide