Fig. 6: Kinetic analysis and performance descriptor of xFe–yMn catalysts in CO2-FTS. | Nature Catalysis

Fig. 6: Kinetic analysis and performance descriptor of xFe–yMn catalysts in CO2-FTS.

From: Understanding Mn-modulated restructuring of Fe-based catalysts for controlling selectivity in CO2 hydrogenation to olefins

Fig. 6

a,b, The rate constant of CO2 adsorption (\({k}_{\text{ads}}^{\text{eff}}({\mathrm{CO}}_2)\)) (a) and the equilibrium constant of CO2 adsorption (\({k}_{\text{ads}}^{\text{eff}}({\mathrm{CO}}_2)/{k}_{\text{des}}({\mathrm{CO}}_2)\)) (b) determined by fitting CO2 responses to a reversible and dissociative CO2 adsorption model (model 4 in Supplementary Table 4) as a function of Mn content in the catalysts. c, The rate of CH4 formation determined in the first segment (r1(CH4) shown in Fig. 2) as a function of \({k}_{\text{ads}}^{\text{eff}}({\mathrm{CO}}_2)/{k}_{\text{des}}({\mathrm{CO}}_2)\). d, The normalized HD formation rate determined by H/D exchange experiments and r1(CH4) as a function of Mn content in the catalysts. e, Relative Gibbs free energy of adsorption (∆Gads) and enthalpy of adsorption (∆Hads) of H2 and C2H4 on Fe5C2(510) and MnO-Fe5C2(510) surfaces under the reaction conditions (T = 350 °C, P = 15 bar and CO2:H2:N2 = 1:3:0.3).

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