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Monometallic Carbonyl‐Derived CeO 2 ‐Supported Rh and Co Bicomponent Catalysts for CO‐Free, High‐Yield H 2 Generation from Low‐Temperature Ethanol Steam Reforming
Author(s) -
Huang Lin,
Choong Catherine,
Chen Luwei,
Wang Zhan,
Zhong Ziyi,
CamposCuerva Carlos,
Lin Jianyi
Publication year - 2013
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.201200452
Subject(s) - catalysis , x ray photoelectron spectroscopy , thermogravimetric analysis , temperature programmed reduction , chemistry , steam reforming , chemisorption , inorganic chemistry , water gas shift reaction , dehydrogenation , rhodium , nuclear chemistry , hydrogen production , chemical engineering , organic chemistry , engineering
CeO 2 ‐supported Rh and Co bicomponent catalysts derived from monometallic carbonyls and prepared from metal nitrates for low‐temperature ethanol steam reforming (ESR) have been studied by catalytic testing using a multi‐channel reactor, temperature‐programmed reduction (TPR), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), H 2 chemisorption, transmission electron microscopy‐energy dispersive X‐ray analysis (TEM‐EDX), powder X‐ray diffraction (PXRD) and IR spectroscopy. Reaction product analysis shows that low‐temperature ESR proceeds mainly through 1) adsorbed oxametallacycle decarbonylation (OD) and acetaldehyde steam reforming (ASR) on Rh/CeO 2 , 2) ethanol dehydrogenation to acetaldehyde, ASR, and water–gas shift (WGS) on Co/CeO 2 , and 3) OD, ASR, and WGS on (Rh+Co)/CeO 2 . The addition of Co to Rh/CeO 2 results in decreased catalytic selectivity towards CO and CH 4 . The carbonyl‐derived (Rh+Co)/CeO 2 displays marked advantage over the nitrate‐prepared catalyst, leading to CO‐free H 2 generation with H 2 yields as high as 4.3 mol H 2 mol C 2 H 5 OH−1 at temperatures as low as 300 °C. Combined studies by TPR, XPS, H 2 chemisorption, and TEM‐EDX suggest significant interaction between the Rh and Co atoms in carbonyl‐derived (Rh+Co)/CeO 2 , in contrast to nitrate‐prepared catalysts, which is assumed to promote efficient WGS during the ESR process. Catalyst deactivation, possibly as a result of catalyst sintering, metal oxidation, and coke deposition during ESR, is discussed in terms of TPR, XPS, TGA, TEM, and PXRD. A WGS‐ESR bilayered catalyst system of Rh/CeO 2 ‐(Rh+Co)/CeO 2 is successfully applied to the CO‐free and high‐yield production of H 2 from low‐temperature ESR.