Facile Synthesis of Defective Porous Sn-Modified CeO₂ Catalyst via Ball Milling-Pyrolysis Method for Efficient Conversion of Biomass-Derived Oxygenates

Abstract

The conversion of biomass-derived oxygenates to sustainable chemicals and renewable fuels is a desirable path, while designing efficient catalysts is key to this process. However, efficiently exposing active sites still remains a significant challenge for improving catalytic performances. In this study, a defective porous Sn-modified CeO 2 (Sn-CeO 2 −BM) catalyst was developed via a facile ball milling-pyrolysis strategy. It showed an excellent catalytic performance in the selective conversion of biomass-derived acetone−n-butanol−ethanol (ABE) fermentation to 4-heptanone. The conversion over Sn-CeO 2 −BM achieved 95% with 82% liquid selectivity of 4-heptanone, which were superior to those over other Sn-modified CeO 2 via conventional synthesis methods. A combination of X-ray diffraction, thermal gravimetric analysis, N 2 adsorption−desorption, Raman, X-ray photoelectron spectroscopy, pyridine IR, transmission electron microscopy, and high-angle annular dark field-scanning transmission electron microscopy provided a comprehensive understanding of its porous structure and defective properties. It was found that the Sn-CeO 2 −BM catalyst displayed a high surface area of 114.86 m 2 •g −1 with a narrow pore size distribution of 4.28 ± 2.2 nm. The Sn species were highly dispersed in the ceria lattice with no remarkable aggregation. It also showed a high oxygen vacancy concentration (1.47) from UV−Raman spectra, which was higher than those of the conventional ceria-supported Sn catalyst (0.68) and Sn-doped ceria (1.44). It was concluded that the efficiently exposed active sites of Sn species and defect sites lead to an excellent catalytic performance of Sn-CeO 2 −BM in the selective conversion of ABE fermentation to 4heptanone. This work proposes a facile way to design and synthesize highly efficient porous CeO 2 -based catalysts.

Improvement of Stability of CeO2–Based Catalysts by Mn Doping for the Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

“…Zr- and Ca-doped CeO 2 catalysts were reported to exhibit higher activity for the DMC production from CO 2 and methanol owing to an increase in the number of oxygen vacancies, which were considered as active sites. , The Cu doping to CeO 2 was also reported to increase the number of oxygen vacancies and strengthen basicity, enhancing the catalytic activity for the DMC synthesis from CO 2 and methanol in the presence of trichloroacetate as a dehydrating agent . According to the previous papers introduced here as well as related reports on tuning of physicochemical properties and performance of CeO 2 -based catalysts, − the modification with heteroatoms is a promising approach to improving the catalytic performance including activity and stability of CeO 2 .…”