Experimental and Theoretical Insights into the Hydrogen-Efficient Direct Hydrodeoxygenation Mechanism of Phenol over Ru/TiO2

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• 作者：Ryan C. Nelson ; Byeongjin Baek ; Pamela Ruiz ; Ben Goundie ; Ashley Brooks ; M. Clayton Wheeler ; Brian G. Frederick ; Lars C. Grabow ; Rachel Narehood Austin
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：November 6, 2015
• 年：2015
• 卷：5
• 期：11
• 页码：6509-6523
• 全文大小：719K
• ISSN：2155-5435

文摘

Catalytic reduction of pyrolyzed biomass is required to remove oxygen and produce transportation fuels, but limited knowledge of how hydrodeoxygenation (HDO) catalysts work stymies the rational design of more efficient and stable catalysts, which in turn limits deployment of biofuels. This work reports results from a novel study utilizing both isotopically labeled phenol (which models the most recalcitrant components of biofuels) with D₂O and DFT calculations to provide insight into the mechanism of the highly efficient HDO catalyst, Ru/TiO₂. The data point to the importance of interface sites between Ru nanoparticles and the TiO₂ support and suggest that water acts as a cocatalyst favoring a direct deoxygenation pathway in which the phenolic OH is replaced directly with H to form benzene. Rather than its reducibility, we propose that the amphoteric nature of TiO₂ facilitates H₂ heterolysis to generate an active site water molecule that promotes the catalytic C鈥揙 bond scission of phenol. This work has clear implications for efforts to scale-up the hydrogen-efficient conversion of wood waste into transportation fuels and biochemicals.