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Catalytic oxidation of cellobiose over TiO2 supported gold-based bimetallic nanoparticles
| Content Provider | Semantic Scholar |
|---|---|
| Author | Amaniampong, Prince Nana Jia, Xinli Wang, Bo Mushrif, Samir H. Borgna, Armando Yang, Yanhui |
| Copyright Year | 2015 |
| Abstract | A series of Au–M (M = Cu, Co, Ru and Pd) bimetallic catalysts were supported on TiO2via a deposition–precipitation (DP) method, using urea as a precipitating agent. The resulting catalysts were employed in the catalytic oxidation of cellobiose to gluconic acid and the properties of these catalysts were carefully examined using various characterization techniques. Cu–Au/TiO2 and Ru–Au/TiO2 catalysts demonstrated excellent catalytic activities in the oxidation of cellobiose to gluconic acid, though with contrasting reaction mechanisms. Complete conversion of cellobiose (100%) with a gluconic acid selectivity of 88.5% at 145 °C within 3 h was observed for reactions performed over Cu–Au/TiO2; whereas, a conversion of 98.3% with a gluconic acid selectivity of 86. 9% at 145 °C within 9 h was observed for reactions performed over Ru–Au/TiO2. A reaction pathway was proposed based on the distribution of reaction products and kinetic data. It is suggested that cellobiose is converted to cellobionic acid (4-O-beta-D-glucopyranosyl-D-gluconic acid) and then gluconic acid is formed through the cleavage of the β-1,4 glycosidic bond in cellobionic acid over Cu–Au/TiO2 catalysts. On the other hand, for reactions over the Ru–Au/TiO2 catalyst, glucose was observed as the reaction intermediate and gluconic acid was formed as a result of glucose oxidation. For reactions over Co–Au/TiO2 and Pd–Au/TiO2 catalysts, fructose was observed as the reaction intermediate, along with small amounts of glucose. Co and Pd remarkably promoted the successive retro-aldol condensation reactions of fructose to glycolic acid, instead of the selective oxidation to gluconic acid. |
| Starting Page | 2393 |
| Ending Page | 2405 |
| Page Count | 13 |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/C4CY01566E |
| Volume Number | 5 |
| Alternate Webpage(s) | http://www.rsc.org/suppdata/cy/c4/c4cy01566e/c4cy01566e1.pdf |
| Alternate Webpage(s) | https://doi.org/10.1039/C4CY01566E |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
