Title: Coverage-Induced Conformational Effects on Activity and Selectivity: Hydrogenation and Decarbonylation of Furfural on Pd(111)

Abstract

Adsorption, hydrogenation, and decarbonylation of furfural on hydrogen-covered Pd(111) was investigated using density functional theory calculations. It was found that both the energy and the conformation of adsorbed furfural vary with increasing coverage of hydrogen or furfural. Furfural lies flat at low coverage but becomes tilted on crowded surfaces. The energy profiles of hydrogenation and decarbonylation reactions on a hydrogen-covered Pd(111) change profoundly compared to those on bare Pd(111). The energy span theory shows that the furfural hydrogenation and decarbonylation effective barriers exhibit a maximum with increasing hydrogen coverage. In contrast, the selectivity to hydrogenation toward furfuryl alcohol over decarbonylation is favored with increasing hydrogen coverage. Microkinetic modeling suggests that the conformation change with increasing H coverage has a significant effect on reaction rates (up to orders of magnitude) and induces a selectivity reversal from furan as the main product (low-H coverage limit) to furfuryl alcohol (high-H coverage limit). Our results may rationalize different selectivity trends seen experimentally under typical reactor and UHV conditions. Importantly, this study underscores the potential importance of operating conditions on hydrodeoxygenation activity and selectivity due to conformational changes of multifunctional biomass derivatives.

Authors:

Wang, Shengguang ^[1]; Vorotnikov, Vassili ^[1]; Vlachos, Dionisios G. ^[1]

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+ Show Author Affiliations

1. Department of Chemical and Biomolecular Engineering, Catalysis Center for Energy Innovation, and Center for Catalytic Science and Technology, University of Delaware, Newark, Delaware 19716, United States

Publication Date:

Tue Nov 25 00:00:00 EST 2014

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Catalysis Center for Energy Innovation (CCEI)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1246455

Alternate Identifier(s):

OSTI ID: 1385128

Grant/Contract Number:  

SC0001004; AC02-05CH11231

Resource Type:

Published Article

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Name: ACS Catalysis Journal Volume: 5 Journal Issue: 1; Journal ID: ISSN 2155-5435

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (homogeneous); catalysis (heterogeneous); biofuels (including algae and biomass); bio-inspired; hydrogen and fuel cells; materials and chemistry by design; synthesis (novel materials); synthesis (self-assembly); synthesis (scalable processing); furfural; furfuryl alcohol; furan; Pd; hydrogenation; decarbonylation; coverage effects; conformation effect; Hydrogen; Aldehydes; Adsorption; Conformation