Cascade Conversion of Cellobiose to Gluconic Acid: The Large Impact of the Small Modification of Electronic Interaction on the Performance of Au/TiO2 Bifunctional Catalysts

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Eblagon, K.M. (Author) FEUP; Luisa M. Pastrana-Martinez (Author) Other; Manuel R. Ribeiro Pereira (Author) FEUP; José L. Figueiredo (Author) Other

Journal

Title: Energy Technology

Vol. 6 No. 9

Pages: 1675-1686

ISSN: 2194-4288

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 5 Citations

INSPEC

Other information

Authenticus ID: P-00P-N21

DOI: 10.1002/ente.201700837

Abstract (EN): The effect of the type and properties of TiO2 and the addition of graphene oxide (GO) was studied in Au/TiO2 bifunctional catalysts, applied for cascade conversion of cellobiose to gluconic acid. Au was supported on three TiO2 materials with varied phase composition (100% anatase or 80% anatase/20% rutile), particle size and surface chemistry. An exceptional yield of gluconic acid reaching 85% was attained in a very short time of only 2hours over Au supported on in-house made TiO2. It was shown that the best performing catalyst had an electron rich Au metal phase and oxygen vacancies situated in close proximity to the metal-support interface. Further, the electronic state in these catalysts was modified by addition of GO to the TiO2 supports, which was followed by high temperature reduction to form TiO2_rGO (TiO2-reduced GO) composites. It was found that the presence of only small amount of rGO hindered the charge transfer from TiO2 to Au, leading to a metallic gold as shown by XPS. In addition, the presence of rGO impeded the formation of oxygen defects in TiO2 supports. This in turn had a negative impact on the rate and selectivity of glucose oxidation, the second step of the tandem process. To sum up, the unique interaction between electron rich Au nanoparticles and the neighboring oxygen vacancies on anatase TiO2 was found to play essential role in obtaining outstanding catalytic performance in the tandem oxidation of cellobiose to gluconic acid.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12