A Comparative Study of Bulk and Supported Chromia Catalysts for the Fluorination of Trichloroethylene

Fluorination of dichlorodifluoromethane to synthesize tetrafluoromethane over Cr2O3–AlF3 catalyst

“…Cr species such as CrO x F y and Cr(OH) x F y are regarded as the active phase for fluorination reaction [17]. Although these species are not observed in the Raman spectra because the Raman peak due to CrO x F y and Cr(OH) x F y are very weak [21,22], they have been readily detected by XPS in our previous work [23] and in other literature [24].…”

“…For the Cr 2 O 3 -Al 2 O 3 catalyst, extended exposure of Al 2 O 3 to fluorinating gases at elevated temperature leads to complete conversion of Al 2 O 3 to AlF 3 , while the maximum degree of fluorination of Cr 2 O 3 remains even after hundreds of hours of contact time. From previous works [2,16,17], CrO x F y and less hydrated amorphous Cr(OH) x F y species considered as the active species of fluorination reaction are observed in fluorinated Cr-based catalysts. However, the CrO x F y and Cr(OH) x F y species are not detected by XRD (Fig.…”

Effects of M-promoter (M=Y, Co, La, Zn) on Cr2O3 catalysts for fluorination of perchloroethylene

“…6 shows the XPS spectra of the Cr 2p level for M-Cr 2 O 3 (F) catalysts. The broad peak of Cr 2p 3/2 could be deconvoluted to two peaks with binding energies of 577.5 and 575.5 eV, which could be assigned to CrO x F y and Cr 2 O 3 , respectively, [31,39,40]. These results indicate that surface Cr species in the M-Cr 2 O 3 (F) catalysts were a mixture of Cr 2 O 3 and CrO x F y .…”

Synthesis and characterization of ultra-fine Cr2O3 from hydrogen reduction of K2CrO4

“…Many researches reported that, the BE of 576.3-576.9 eV [15][16][17][18][19][20] is a characteristic for Cr 3+ , and the supported Cr 3+ has a higher BE than the bulk chromium (III) oxide. Therefore, the peak at 576.4 eV can be assigned to Cr 3+ .The peak at 577.6 eV may be assigned to the mixed valence of Cr 3+ and Cr 4+ [18] or the valence of Cr 3+ in Cr(OH) 3 [19] .…”