Highly efficient Ni/CeO2-Al2O3 catalysts for CO2 upgrading via reverse water-gas shift: Effect of selected transition metal promoters

In the context of Carbon Capture and Utilisation (CCU), the catalytic reduction of CO2 to CO via reverse water-gas shift (RWGS) reaction is a desirable route for CO2 valorisation. Herein, we have developed highly effective Ni-based catalysts for this reaction. Our study reveals that CeO2-Al2O3 is an excellent support for this process helping to achieve high degrees of CO2 conversions. Interestingly, FeOx and CrOx, which are well-known active components for the forward shift reaction, have opposite effects when used as promoters in the RWGS reaction. The use of iron remarkably boosts the activity, selectivity and stability of the Ni-based catalysts, while adding chromium results detrimental to the overall catalytic performance. In fact, the iron-doped material was tested under extreme conditions (in terms of space velocity) displaying fairly good activity/stability results. This indicates that this sort of catalysts could be potentially used to design compact RWGS reactors for flexible CO2 utilisation units.Financial support for this work was provided by the Department of Chemical and Process Engineering at the University of Surrey and the EPSRC projects EP/J020184/2 and EP/R512904/1 as well as the Royal Society Research Grant RSGR1180353. The Spanish team acknowledges Ministerio de Economia, Industria y Competitividad of Spain (Project MAT2013-45008-P). LPP also thanks Comunitat Valenciana for her postdoctoral fellow (APOSTD2017)