(425c) Indium Oxide with SAPO-34 Bifunctional Catalyst for CO2 Hydrogenation to Light Olefins

Authors: 
Kim, S., University of South Carolina
Lauterbach, J., University of South Carolina
Sasmaz, E., University of California, Irvine
Light olefins (C2–C4) can be produced from CO2 hydrogenation by bifunctional catalyst via methanol intermediate route of which CO2 is first converted to methanol on metal oxides followed by methanol-to-olefins (MTO) reaction on zeolite in a single reactor. This process can produce higher C2–C4 olefins selectivity than a modified Fischer–Tropsch synthesis (FTS) route. In the present work, indium supported on ZrO2 was mixed with SAPO-34, and the catalysts were evaluated for direct CO2 hydrogenation at a temperature range from 300 ºC to 400 ºC at 30 bar. Our results show that 10 wt.% In/ZrO2 has a CO2 conversion of 7.0%, 17.4%, and 32.9% at the reaction temperature of 300 ºC, 350 ºC, and 400 ºC, respectively. At the temperature of 350 ºC, the space-time yield (STY) has the highest value of 1.25 mmol/h/g among the scanned temperatures, and the selectivity of CO, CH4, olefins, and paraffins is 60.7%, 1.1%, 21.3%, and 16.9% at 350 ºC, respectively. The major produced gas of CO related with the reverse-water gas shift reaction can be minimized, and the activity and light olefins selectivity can be increased by incorporating promoters and controlling interaction between In/ZrO2 and SAPO-34. In this presentation, we will illustrate a detailed characterization of the catalyst using electron microscopy and x-ray spectroscopy, discuss the reaction mechanism of the catalyst, and elucidate the effect of promoter and catalyst structure on olefins selectivity.