The authors are grateful to Dr. N. Perret for her involvement in this work. EPSRC support for free access to the TEM facility at the University of St. Andrews and financial support to Dr. M. Li and Dr. X. Wang through the Overseas Research Students Award Scheme (ORSAS) are also acknowledged.Peer reviewedPostprin

Cárdenas-Lizana, Fernando

Keane, Mark A.

Li, Maoshuai

Wang, Xiaodong

Catalysis Today

English

A range of oxides (γ-Al2O3, TiO2, ZrO2, CeO2, α-Fe2O3 and Fe3O4) with different redox properties were used to support nano-scale (mean = 2-8 nm) Au and employed in the gas phase hydrogenation of benzaldehyde and nitrobenzene. The catalysts were subjected to TPR, H2/O2 titration, H2 TPD, XRD, TEM/STEM and XPS analysis. The supported Au phase promoted partial reduction of the reducible supports through the action of spillover hydrogen (based on TPD), which generated surface oxygen vacancies (demonstrated by O2 titration) that inhibit Au particle sintering during catalyst activation. Electron transfer to generate charged Au species (determined by XPS) correlates with support ionisation potential. Higher nitrobenzene hydrogenation (to aniline) TOFs were recorded relative to benzaldehyde where rate increased with decreasing Au size (from 8 to 4 nm) with measurably lower TOF over Au &lt;3 nm. Strong binding of –CH=O and –NO2 functions to oxygen vacancies resulted in lower hydrogenation rates. Higher temperatures (&gt;413 K) promoted benzaldehyde hydrogenolysis to toluene and benzene. The formation of Auδ- on non-reducible Al2O3 favoured selective reduction of –CH=O with full selectivity to benzyl alcohol at 413 K

Cardenas-Lizana, Fernando

Heriot Watt Pure

Effect of support redox character on catalytic performance in the gas phase hydrogenation of benzaldehyde and nitrobenzene over supported gold

Maoshuai Li

Xiaodong Wang

Fernando Cárdenas-Lizana

Mark A. Keane

Crossref

A range of oxides (γ-Al2O3, TiO2, ZrO2, CeO2, α-Fe2O3 and Fe3O4) with different redox properties were used to support nano-scale (mean = 2–8 nm) Au and employed in the gas phase hydrogenation of benzaldehyde and nitrobenzene. The catalysts were subjected to TPR, H2/O2 titration, H2 TPD, XRD, TEM/STEM and XPS analysis. The supported Au phase promoted partial reduction of the reducible supports through the action of spillover hydrogen (based on TPD), which generated surface oxygen vacancies (demonstrated by O2 titration) that inhibit Au particle sintering during catalyst activation. Electron transfer to generate charged Au species (determined by XPS) correlates with support ionisation potential. Higher nitrobenzene hydrogenation (to aniline) TOFs were recorded relative to benzaldehyde where rate increased with decreasing Au size (from 8 to 4 nm) with measurably lower TOF over Au 413 K) promoted benzaldehyde hydrogenolysis to toluene and benzene. The formation of Auδ− on non-reducible Al2O3 favoured selective reduction of CHO with full selectivity to benzyl alcohol at 413 K

Lancaster E-Prints

The authors are grateful to Dr. N. Perret for her involvement in this work. EPSRC support for free access to the TEM facility at the University of St. Andrews and financial support to Dr. M. Li and Dr. X. Wang through the Overseas Research Students Award Scheme (ORSAS) are also acknowledged.Peer reviewe

The Open University

Effect of support redox character on catalytic performance in the gas phase hydrogenation of benzaldehyde and nitrobenzene over supported gold

https://eprints.lancs.ac.uk/id/eprint/136875/1/CATTOD_D_15_00697R1_in_press.pdf

Effect of support redox character on catalytic performance in the gas phase hydrogenation of benzaldehyde and nitrobenzene over supported gold

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Heriot Watt Pure

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Lancaster E-Prints

Heriot Watt Pure

The Open University

Heriot Watt Pure