A series of Co-Fe bimetallic catalysts was prepared, characterized, and studied for the hydrogenation of carbon dioxide. The catalyst precursors were prepared via an oxalate coprecipitation method. Monometallic (Co or Fe) and bimetallic (Co-Fe) oxalate precursors were decomposed under a N2 flow at 400°C and further pretreated under a CO flow at 250°C. The catalysts (before decomposition of the oxalates or after activation) were characterized by BET, TGA-MS, X-ray diffraction, CO-TPR, SEM, HR-TEM, and Mössbauer spectroscopy techniques. The hydrogenation reaction of CO2 was performed using Co-Fe bimetallic catalysts pretreated in situ in a fixed-bed catalytic microreactor operating in the temperature range of 200-270°C and a pressure of 0.92 MPa. With increasing Fe fraction, the selectivity to C2-C4 for Co-Fe catalyst increased under all operating conditions. The alcohol selectivity was found to increase with increasing iron content of the Co-Fe catalyst up to 50%, but then it dropped with further addition of iron. Among the three different activation conditions, the CO pretreated Co-Fe (50Co50Fe) catalyst exhibited a much lower selectivity for methane. Addition of 1 wt % Na or 1.7 wt % K to 50Co50Fe catalyst increases its olefinic (C2-C4) and oxygenate selectivities.
|Number of pages||15|
|State||Published - Feb 5 2016|
Bibliographical notePublisher Copyright:
© 2015 American Chemical Society.
- carbon dioxide (CO) hydrogenation
- Co-Fe bimetallic catalyst
- cobalt carbide
- iron carbides
- Mössbauer spectroscopy
- oxalates coprecipitation method
ASJC Scopus subject areas
- Chemistry (all)