Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel The effect of lanthanide promoters on NiInAl/SiO 2 catalyst for methanol synthesis Anthony R. Richard a , Maohong Fan a,b, ⁎ a Department of Chemical Engineering, University of Wyoming, Laramie, WY 82071, USA b School of Energy Resources, University of Wyoming, Laramie, WY 82071, USA GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Lanthanides Rare earth elements Methanol synthesis CO2 utilization Nickel indium catalyst ABSTRACT The addition of lanthanides, or rare earth elements, as promoters to NiInAl/SiO 2 methanol synthesis catalysts was investigated. The promoters studied are the light rare earth elements (La to Gd) and all but La and Ce were shown to improve methanol synthesis activity. A comparison of the synthesis method for introduction of Pr as a promoter found that addition during the deposition-precipitation synthesis of the catalyst is superior to incipient wetness impregnation introduction after synthesis. The heaviest lanthanides tested (Sm, Eu, Gd) showed the greatest improvement in methanol synthesis activity and selectivity, with a concomitant decrease of CO pro- duced. The Gd-promoted catalyst showed the greatest increase in methanol synthesis activity at 0.51 mmol g cat -1 h -1 which is a 27% increase over the catalyst with no promoter. Examination of the basic characteristics of the catalysts by CO 2 TPD and in situ FTIR revealed a negative correlation between basicity and methanol synthesis activity. FTIR methanol synthesis tests also revealed a larger proportion of the key inter- mediate, bidentate formate, with the addition of the Gd promoter. STEM micrographs and particle size dis- tributions show that the incorporation of the Gd promoter results in smaller diameter metallic particles and higher resistance to sintering. EELS mapping revealed that the location of Ni and Gd correlates well with the metallic particles observed with STEM, and while the In is also found in these particles, small amounts are also observed to be dispersed outside of the particles. https://doi.org/10.1016/j.fuel.2018.02.185 Received 24 December 2017; Received in revised form 24 February 2018; Accepted 28 February 2018 ⁎ Corresponding author at: Department of Chemical Engineering, University of Wyoming, Laramie, WY 82071, USA. E-mail address: mfan@uwyo.edu (M. Fan). Fuel 222 (2018) 513–522 Available online 23 March 2018 0016-2361/ © 2018 Elsevier Ltd. All rights reserved. T