文献类型：期刊文献

英文题名：Controlling Selectivity in Unsaturated Aldehyde Hydrogenation Using Single-Site Alloy Catalysts

作者：Cao, Yueqiang[1,2,3];Chen, Bo[1,2];Guerrero-Sanchez, Jonathan[4];Lee, Ilkeun[1,2];Zhou, Xinggui[3];Takeuchi, Noboru[1,2,4];Zaera, Francisco[1,2]

机构：[1]Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA;[2]Univ Calif Riverside, Ctr Catalysis, Riverside, CA 92521 USA;[3]East China Univ Sci & Technol, State Key Lab Chem Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China;[4]Univ Nacl Autonoma Mexico, Ctr Nanociencias & Nanotecnol, Apartado Postal 14, Ensenada 22800, Baja California, Mexico

年份：2019

卷号：9

期号：10

起止页码：9150

外文期刊名：ACS CATALYSIS

收录：;EI(收录号：20194207530469);WOS:【SCI-EXPANDED(收录号:WOS:000489204000034)】；

基金：Financial support for this project was provided by a grant from the U.S. National Science Foundation, Division of Chemistry (NSF-CHE 1660433). YC acknowledges the 111 project of China (grant no. B08021, Ministry of Education of the People's Republic of China and State Administration of Foreign Experts Affairs of People's Republic of China) for traveling support for his visit to Riverside to perform the reported experiments. N.T. and J.G.S. thank DGAPA-UNAM project IN100516 and Conacyt grant A1-S-9070 for partial financial support. N.T. thanks DGAPA-UNAM for a sabbatical scholarship at the University of California, Riverside. Calculations were performed in the DGCTIC-UNAM Supercomputing Center, project LANCAD-UNAM-DGTIC-051.

语种：英文

外文关键词：selective hydrogenation; unsaturated aldehydes; alloy catalysts; platinum; copper; infrared absorption spectroscopy; DFT; surface chemistry

摘要：Selectivity in catalysis is key to many industrial processes, yet it is often difficult to control. One promising approach is to use so-called single-atom catalysts, whereby one catalytic component is isolated within a second phase to add a key but otherwise unavailable functionality. Here, we report the use of metal alloys consisting of Pt single atoms diluted within Cu nanoparticles to selectively promote the hydrogenation of C=O bonds in unsaturated aldehydes, a reaction of interest in fine chemical manufacturing. Our rationale, that Cu surfaces may favor C=O over C=C hydrogenation steps with atomic hydrogen but may require Pt sites to promote the initial activation of molecular hydrogen, was corroborated by kinetic catalytic experiments. However, fundamental surface science studies and quantum mechanics calculations showed that the explanation for the observed catalytic performance is more nuanced. For one, titration experiments using carbon monoxide failed to identify Pt atoms accessible on the surface of the catalysts, suggesting that their catalytic contribution may involve indirect electronic changes on neighboring Cu atoms. In addition, infrared absorption and X-ray photoelectron spectroscopy results identified the existence of a thin Cu oxide layer covering the metallic nanoparticles. Finally, it was determined that hydrogenation selectivity with Cu-based catalysts may be explained in part by their preference for bonding unsaturated aldehydes via the terminal oxygen atom but is also affected by competitive adsorption among the reactants and products. Single-atom alloy catalysts appear to indeed help with selectivity in hydrogenation catalysis, but more in situ (or operando) characterization experiments are needed to better understand how they operate.