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The Influence of the Precipitation/Ageing Temperature on a Cu/ZnO/ZrO 2 Catalyst for Methanol Synthesis from H 2 and CO 2
Author(s) -
Frei Elias,
Schaadt Achim,
Ludwig Thilo,
Hillebrecht Harald,
Krossing Ingo
Publication year - 2014
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.201300665
Subject(s) - catalysis , methanol , crystallinity , coprecipitation , precipitation , malachite , space velocity , fourier transform infrared spectroscopy , materials science , chemistry , inorganic chemistry , chemical engineering , nuclear chemistry , copper , metallurgy , selectivity , crystallography , organic chemistry , physics , meteorology , engineering
For heterogeneous catalysts, the constitution of the precursor is an important parameter to adjust the properties of the active catalyst. Therefore, we examined the influence of the temperature during the precipitation process and during the ageing time in the mother liquor for a Cu/ZnO/ZrO 2 catalyst system obtained through a coprecipitation route. The variation of the temperature affects the ratio and crystallinity of the precursor phases zincian malachite and aurichalcite, as detected by powder XRD (phase and line width) and FTIR spectroscopy (characteristic asymmetric CO stretching modes of the carbonate anions at $\tilde \nu $ =1600–1100 cm −1 ). Therefore, the precatalyst surface area ( A s,BET ) and pore distribution are adjustable (i.e., A s,BET of 190 m 2 g −1 was reached). The influence of the synthesis conditions on the catalysts activity for methanol production was analyzed and discussed up to the level of productivity/activity testing at 413/513 K and 40 bar total H 2 /CO 2 pressure. The best catalyst showed a methanol productivity of 9.16 mmol g cat −1 h −1 (513 K, 40 bar, and gas hourly space velocity=8000) and is better than an industrial catalyst tested under the same conditions (8.34 mmol g cat −1 h −1 ). However, despite considerable differences in the precursor and precatalyst structure and morphology, their influence on the methanol productivity is only small. This demonstrates that the active catalyst is formed under reaction conditions.