Abstract
M-Co-Al (M = Ca, La, Li or Mg) materials were synthesised by co-precipitation and investigated for dry reforming of methane. Thermogravimetry, temperature-programmed oxidation, reduction and CO2 desorption, specific area and X-ray diffraction were utilised for characterisation. Activity tests were conducted at atmospheric pressure, temperatures between 400-550oC , CH4/CO2 molar ratio of 1 and GHSV of 6000 NmL CH4·g-1·h-1. The partial substitution of Co by a third element increased the area and changed the acid/base properties, reducibility and crystallinity of the oxides. These modifications resulted in higher activity for dry reforming of methane, mainly related to the decrease in the acidity of the promoted materials and, consequently, lower carbon formation. The Li-modified sample presented the lowest coke deposition due to the increase in stronger basic sites. The Mg-promoted catalyst exhibited the best activity performance. This depicts the enhancement in the reducibility and acid/base properties found in the MgCoAl sample.
Highlights
Carbon dioxide reforming of methane is an interesting route for converting natural gas into synthesis gas, which can generate a wide range of products such as clean transportation fuels and other chemicals
The thermogravimetric curves obtained for the LiCoAl sample are presented in Figure 1, which includes the derivative thermogravimetric analysis (DTG) and the differential thermal analysis (DTA)
The position and the relative intensity of the DTG peaks are similar to the results reported by Wang et al.[40] for Co-Al catalysts synthesised with a similar method
Summary
Carbon dioxide reforming of methane is an interesting route for converting natural gas into synthesis gas (or syngas), which can generate a wide range of products such as clean transportation fuels and other chemicals. This promotion can be performed by adding the alkali directly during the synthesis of co-precipitated samples This preparation method can originate mixed oxides, which have desirable properties such as high surface area, high thermal stability and small crystallite sizes[20,21]. Materials Research similar mixed oxide materials based on cobalt in different processes[29,30,31], and these results lead to the investigation of dry reforming of CH4 on Co-mixed oxide catalysts. The present work investigates the two mentioned strategies, i.e., the CO2 reforming of methane over Co-Al mixed oxide materials modified with alkali elements such as Ca, La, Li or Mg. The third element was chosen based on the effect of slowing down the reoxidation of metallic Ni or Co described earlier. The different charges and ionic radii, which increase in the order Li+ < Mg2+ < Co2+ < Ca2+ < La3+, were taken into account for selecting the metal because these properties can lead to different structures of the mixed oxides
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
