Synthesis of Ethanol from Syngas over Rh/MCM-41 Catalyst: Effect of Water on Product Selectivity
2015 (English)In: CATALYSTS, ISSN 2073-4344, Vol. 5, no 4, 1737-1755 p.Article in journal (Refereed) PublishedText
The thermochemical processing of biomass is an alternative route for the manufacture of fuel-grade ethanol, in which the catalytic conversion of syngas to ethanol is a key step. The search for novel catalyst formulations, active sites and types of support is of current interest. In this work, the catalytic performance of an Rh/MCM-41 catalyst has been evaluated and compared with a typical Rh/SiO2 catalyst. They have been compared at identical reaction conditions (280 degrees C and 20 bar), at low syngas conversion (2.8%) and at same metal dispersion (H/Rh = 22%). Under these conditions, the catalysts showed different product selectivities. The differences have been attributed to the concentration of water vapor in the pores of Rh/MCM-41. The concentration of water vapor could promote the water-gas-shift-reaction generating some extra carbon dioxide and hydrogen, which in turn can induce side reactions and change the product selectivity. The extra hydrogen generated could facilitate the hydrogenation of a C-2-oxygenated intermediate to ethanol, thus resulting in a higher ethanol selectivity over the Rh/MCM-41 catalyst as compared to the typical Rh/SiO2 catalyst; 24% and 8%, respectively. The catalysts have been characterized, before and after reaction, by N-2-physisorption, X-ray photoelectron spectroscopy, X-ray diffraction, H-2-chemisorption, transmission electron microscopy and temperature programmed reduction.
Place, publisher, year, edition, pages
MDPI AG , 2015. Vol. 5, no 4, 1737-1755 p.
ethanol, syngas, Rh/MCM-41 catalyst, water vapor
IdentifiersURN: urn:nbn:se:kth:diva-180993DOI: 10.3390/catal5041737ISI: 000367535300008ScopusID: 2-s2.0-84944885472OAI: oai:DiVA.org:kth-180993DiVA: diva2:898193
QC 201601272016-01-272016-01-262016-01-29Bibliographically approved