Design and synthesis of copper-cobalt catalysts for the selective conversion of synthesis gas to ethanol and higher alcohols.
Combining quantum-mechanical simulations and synthesis tools allows the design of highly efficient CuCo/MoO(x) catalysts for the selective conversion of synthesis gas (CO+H2) into ethanol and higher alcohols, which are of eminent interest for the production of platform chemicals from non-petroleum feedstocks. Density functional theory calculations coupled to microkinetic models identify mixed Cu-Co alloy sites, at Co-enriched surfaces, as ideal for the selective production of long-chain alcohols. Accordingly, a versatile synthesis route is developed based on metal nanoparticle exsolution from a molybdate precursor compound whose crystalline structure isomorphically accommodates Cu(2+) and Co(2+) cations in a wide range of compositions. As revealed by energy-dispersive X-ray nanospectroscopy and temperature-resolved X-ray diffraction, superior mixing of Cu and Co species promotes formation of CuCo alloy nanocrystals after activation, leading to two orders of magnitude higher yield to high alcohols than a benchmark CuCoCr catalyst. Substantiating simulations, the yield to high alcohols is maximized in parallel to the CuCo alloy contribution, for Co-rich surface compositions, for which Cu phase segregation is prevented.
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG, Utrecht (The Netherlands).
Gonzalo
G
Prieto
Steven
S
Beijer
Miranda L
ML
Smith
Ming
M
He
Yuen
Y
Au
Zi
Z
Wang
David A
DA
Bruce
Krijn P
KP
de Jong
James J
JJ
Spivey
Petra E
PE
de Jongh
CO hydrogenation; alloy nanoparticles; heterogeneous catalysis; high alcohols; supported catalysts