A disordered model based on metal atoms located in 2a Wyckoff positions (WP) (Co: 50%, Fe: 50% confirmed by SEM-EDS, Fig. ) and the 4f WP statistically occupied by oxygen atoms (25%) and fluorine atoms (75%) was used for Rietveld refinement of Co0.5Fe0.5O0.5F1.5 PXRD pattern (space group P42/mnm). A good fit was obtained in spite of the low crystallinity with the cell parameters: a = b = 4.6916(5) Å, c = 3.1098(3) Å, V = 68.450(1) Å 3 (Fig. ). The broadening of the Bragg diffraction peaks, compared to the diffraction pattern of the precursor (Fig. ), reveals small coherent diffraction domains. Indeed, an emerging porosity is observed which is likely related to the precursor's decomposition during which HF and H2O gas molecules act as a self-generated porogen (Fig. ). Upon thermal treatment SBET increases from 3 m 2 .g -1 to 24 m 2 .g -1 confirming the porogen effect of the H2O and HF released. N2 adsorption/desorption isotherms shows type IV hysteresis corresponding to a mesoporous structure and the BJH pore-size distribution analysis (Fig. ) confirms an average pore diameter less than 10 nm, in good agreement with the TEM observation (Fig. ). 57 Fe Mössbauer spectra (Fig. ) and the hyperfine data, in particular  = 0.39 and 0.46 mm.s -1 at 300 and 77K, respectively, are consistent with the presence of only Fe 3+ species with different atomic environments, resulting from: (i) the presence of octahedral units with shared corners and shared edges, (ii) Fe-Co cationic disorder, and (iii) small crystal grain size, consistent with X-ray analysis. X-ray photoelectron spectroscopy was used to measure the electronic structure of both of the Co and Fe components in Co0.5Fe0.5O0.5F1.5. The Fe 2p3/2 edge could be fit to two components at 710.7 and 712.7 eV (Fig. ). These values match that of Fe 3+ and fall between that of Fe in a pure oxide and a pure fluoride environment. The Co 2p3/2 peak has a primary feature at 781.7 eV, with a satellite at 786.4 eV which is in between the expected ranges of pure Co fluorides and oxides (Fig. ). These measurements illustrate the strong inductive effects imparted through the fluoride components within the lattice hypothesized earlier to influence the catalytic properties of the composite material.