Structural Properties of Spinel Ferrite Catalysts for Co2 Reduction Via Reverse Water Gas Shift Reaction

Abstract

The production of CO via Reverse Water Gas Shift (RWGS) reaction is a suitable route for CO 2 valorization. Herein, a series of modified-ferrites AFe 2 O 4 (A = Ni, Zn, Mn and Cu) are investigated as RWGS catalysts and the structure to function relationships derived from changes on the A-site cation are rationalized. For all ferrite systems, the RWGS reaction was identified as the governing pathway for CO 2 conversion underlining that the process selectivity is governed by the B-site cation. The variations on the A-site metals though determined the catalysts’ structural features and affected the RWGS performance. Among the catalyst series, the superior RWGS performance displayed by CuFe 2 O 4 and NiFe 2 O 4 inverse spinels was associated to the greater oxygen vacancy population enabled by the partial allocation on Fe 3+ cations into the tetrahedral site, i.e. the constitution of inverse-like spinels. As a function of the A-site cation, interconnections between the oxygen vacancy concentration and the RWGS performance are established.