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Stearate‐Based Cu Colloids in Methanol Synthesis: Structural Changes Driven by Strong Metal–Support Interactions
Author(s) -
Schimpf Sabine,
Rittermeier André,
Zhang Xiaoning,
Li ZiAn,
Spasova Marina,
van den Berg Mauritz W. E.,
Farle Michael,
Wang Yuemin,
Fischer Roland A.,
Muhler Martin
Publication year - 2010
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.200900252
Subject(s) - catalysis , methanol , stearate , chemical engineering , materials science , nanoparticle , transmission electron microscopy , zinc stearate , metal , colloid , ternary operation , hydrolysis , phase (matter) , inorganic chemistry , crystallography , chemistry , nanotechnology , metallurgy , organic chemistry , composite material , raw material , computer science , engineering , programming language
Metal stearate‐stabilized Cu nanoparticles, synthesized by an efficient one‐step process, were applied in the continuous liquid‐phase synthesis of methanol. After optimizing the reduction procedure, twofold higher rates of methanol formation were found for Cu–Zn colloids, compared to the conventional ternary Cu/ZnO/Al 2 O 3 catalyst applied as fine powder in the liquid phase. Structural changes were investigated as a function of time on stream; after reduction in H 2 , spherical, well‐separated 5–10 nm Cu particles stabilized by a Zn stearate shell were found. Under catalytic high‐pressure conditions Zn stearate was hydrolyzed forming ZnO. High‐resolution transmission electron microscopy revealed the presence of triangular ZnO prisms with truncated edges. Applying optimized synthesis conditions these triangularly shaped ZnO particles were found to be mostly attached to the spherical Cu particles. The catalytic results and the structural and spectroscopic characterization suggest that these ZnO particles act as a reservoir, releasing ZnO x species, which diffuse onto the Cu particles and promote the catalytic activity.