@article{sun_schulz_thompson_lamb_2016, title={Catalytic deoxygenation of octanoic acid over silica- and carbon-supported palladium: Support effects and reaction pathways}, volume={269}, ISSN={["1873-4308"]}, DOI={10.1016/j.cattod.2015.12.021}, abstractNote={Octanoic acid (OA) deoxygenation was investigated over silica- and carbon-supported palladium catalysts (each containing 5 wt.% Pd) at 235–300 °C and 1 atm in a continuous flow reactor. A commercial Pd/SiO2 (A) catalyst was active for OA decarbonylation (DCN) and hydrodeoxygenation (HDO) at 260 °C under 10% H2; subsequent hydrogenation (HY) and DCN of the primary products, 1-heptene and octanal, respectively, produced n-heptane. Under equivalent conditions, a Pd/SiO2 (B) catalyst prepared using Pd(NO3)2 and Aerosil 300 produced n-heptane with very high selectivity (>99%) via DCN/HY. In contrast, a commercial Pd/C (A) catalyst was highly active and selective to n-heptane (>98%) and CO2 (65%) under these conditions. Moreover, CO2 selectivity and n-heptane yield increased with reaction temperature consistent with direct decarboxylation (DCX). Increasing H2 partial pressure resulted in markedly lower activity and CO2 selectivity; however, Pd/C (A) had negligible activity under He. Pd/C (A) exhibited greater water–gas shift (WGS) activity than Pd/SiO2 (A); however, differences in WGS activity alone cannot explain the observed support effect. A more highly dispersed Pd/C (B) catalyst was more active at 260 °C under H2 than Pd/C (A); however, under 10% H2, it had lower activity, CO2 selectivity (55%), and stability. Pd/C (A) and Pd/C (B) have very similar textural properties, but Pd/C (A) has a much higher Na content. By comparison, Pd supported on high-purity acetylene carbon black exhibited only DCN activity. These results indicate that carbon surface properties (e.g., polar functional groups, alkali metal content) influence the fatty acid deoxygenation performance of Pd/C catalysts.}, journal={CATALYSIS TODAY}, author={Sun, Keyi and Schulz, Taylor C. and Thompson, Simon T. and Lamb, H. Henry}, year={2016}, month={Jul}, pages={93–102} }
 @article{sun_wilson_thompson_lamb_2015, title={Catalytic Deoxygenation of Octanoic Acid over Supported Palladium: Effects of Particle Size and Alloying with Gold}, volume={5}, ISSN={["2155-5435"]}, DOI={10.1021/cs501865n}, abstractNote={Catalytic deoxygenation of octanoic acid (OA) to n-heptane was investigated over silica-supported Pd and PdAu catalysts at 260 °C and 1 atm in a fixed-bed microreactor. Pd/SiO2 catalysts were prepared by incipient wetness (IW) and ion exchange (IE). Bimetallic catalysts were prepared using an IE procedure that is known to produce supported PdAu nanoparticles. The Pd nanoparticles (7.5 nm average size) in the Pd/SiO2 (IW) catalyst exhibit well-defined (100) and (111) facets, as evidenced by high-resolution electron microscopy (HREM) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of adsorbed CO. As expected, the smaller nanoparticles (1.5 nm average size) in the Pd/SiO2 (IE) catalyst display strong linear and bridging CO DRIFTS bands. The PdAu/SiO2 (1/1 atomic ratio) catalyst contains 5 nm alloy nanoparticles with Pd-rich surfaces, as evidenced by HREM with energy-dispersive X-ray (EDX) analysis and in situ EXAFS spectroscopy. DRIFTS thermal desorption experiments demonstrated that alloying with Au reduced the CO adsorption energy on surface Pd sites. The Pd/SiO2 (IE) catalyst initially exhibited OA decarboxylation and decarbonylation activity but lost decarboxylation activity rapidly with time on stream (TOS). In contrast, the Pd/SiO2 (IW) catalyst had only decarbonylation activity, deactivated less rapidly with TOS, and could be regenerated by heating in H2 to remove OA residues. Alloying Pd with Au was found to improve catalyst stability without significantly affecting decarbonylation activity, as evidenced by the equivalent OA turnover frequencies of the Pd/SiO2 (IW) and PdAu/SiO2 (2/3) catalysts. The geometric and electronic effects of alloying reduce the CO adsorption energy and mitigate self-poisoning by OA and related species.}, number={3}, journal={ACS CATALYSIS}, author={Sun, Keyi and Wilson, Adria R. and Thompson, Simon T. and Lamb, H. Henry}, year={2015}, month={Mar}, pages={1939–1948} }
 @article{wilson_sun_chi_white_lebeau_lamb_wiley_2013, title={From Core-Shell to Alloys: The Preparation and Characterization of Solution-Synthesized AuPd Nanoparticle Catalysts}, volume={117}, ISSN={["1932-7447"]}, DOI={10.1021/jp404157m}, abstractNote={This article describes the solution-phase synthesis of 4 nm gold nanoparticles with 0.7 atom-thick, 1.9 atom-thick, and 3.8 atom-thick layers of Pd on their surfaces. These well-defined core–shell nanoparticles were deposited on a silica support, calcined, and reduced at 300 °C to create alloyed nanoparticles containing 10.9, 20.2, and 28.5% Pd (w/w). Monometallic Pd nanoparticles sintered during calcination at 300 °C, but no sintering was observed for AuPd nanoparticles. Diffuse reflectance infrared Fourier transform (DRIFT) spectra of adsorbed CO suggests that Au donates d electron density to Pd in the core–shell and alloy structures and confirms the presence of Au and Pd atoms on the surface of the nanoparticles after calcination and reduction. The properties of the AuPd alloy catalysts were tested in the vapor-phase conversion of α-limonene to p-cymene. AuPd nanoparticles containing 20% or more Pd per particle produced p-cymene yields greater than 80%, equivalent to conventional Pd catalysts prepared by incipient wetness and ion exchange methods. Very low yields of p-cymene were obtained from dehydrogenation of p-menthane under equivalent conditions, suggesting that the production of p-cymene from α-limonene proceeds through terpinene intermediates.}, number={34}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Wilson, Adria R. and Sun, Keyi and Chi, Miaofang and White, Ryan M. and LeBeau, James M. and Lamb, H. Henry and Wiley, Benjamin J.}, year={2013}, month={Aug}, pages={17557–17566} }