Catalytic Decomposition of N₂O over Co–Ti Oxide Catalysts: Interaction between Co and Ti Oxide

Abstract

A series of CoxTi catalysts with different Co/Ti molar ratios (x=0.2, 0.4, 0.6, and 0.8) were prepared by the sol‐gel method and used for N2O decomposition. The catalysts were characterized by XRD, X‐ray photoelectron spectroscopy (XPS), TEM, temperature‐programmed reduction with H2, temperature‐programmed desorption of O2, diffuse reflectance UV/Vis, Raman spectra, and N2 adsorption–desorption measurements. The results indicate that the CoxTi catalysts possess high Brunauer–Emmett–Teller (BET) surface area, more surface Co3+, and even better structural stability than Co3O4 as a result of the strong interactions between Co and Ti oxide. Deactivation occurred over time for the Co3O4 catalyst, however, Co0.6Ti maintains nearly 100 % N2O conversion for at least 30 h. Moreover, the Co0.6Ti catalyst showed much stronger resistance against 1.5 vol. % O2, 2.4 vol. % H2O, or 1.6 vol. % NO in the feed compared with the Co3O4 catalyst. The excellent activity of the Co0.6Ti catalyst can be attributed to the higher amount of surface Co3+ derived from the interaction of the Co and Ti oxide in the CoxTi catalysts.

Strong Structural Modification of Gd to Co3O4for Catalyzing N2O Decomposition under Simulated Real Tail Gases

“…10,13 To understand more deeply, the Co 2p 3/2 XPS spectra of the pure Co 3 O 4 and Gd 0.06 Co catalysts were resolved into two peaks at ∼781.0 and ∼779.5 eV, which can be attributed to the surface Co 2+ and Co 3+ species, respectively. 48 According to the integrated area of the corresponding peak, the molar ratios of the surface Co 3+ /Co 2+ for pure Co 3 O 4 and Gd 0.06 Co were calculated, as shown in Table 3, which were 0.89 and 1.69, respectively. By combining the HR-TEM results, it can be speculated that the appearance of (400), (440), and (511) crystal faces caused by the strong crystallite size reduction effect of Gd on Co 3 O 4 was the main reason for the Gd 0.06 Co catalyst to possess a higher surface Co 3+ /Co 2+ ratio compared with pure Co 3 O 4 .…”

Taming the Redox Property of A0.5Co2.5O4 (A = Mg, Ca, Sr, Ba) toward High Catalytic Activity for N2O Decomposition

“…Figure A shows the Co 2p spectra of A 0.5 Co 2.5 O 4 . Two characteristic diffraction peaks attributable to Co 2p 1/2 and Co 2p 3/2 are noted at around 793.5 and 778.5 eV. − The Co 2p 3/2 spectra were divided into Co 2+ and Co 3+ characteristic peaks of valence states, and the fitting results are listed in Table . Note that the binding energy of the Co 2p 3/2 peak of the Co 3 O 4 catalyst is at 779.1 eV.…”

Impact of composition and structural parameters on the catalytic activity of MFI type titanosilicalites

“…In the literature, various noble metals have been considered as the main catalysts for the decomposition of nitrous oxide, such as Rh 11 and Ru 12 deposited on various oxide and zeolite supports. In addition, metal-containing zeolites are considered to be cheaper systems [13][14][15] than oxide 16 or perovskite systems. 17 Titanium oxide is considered mainly as a support 11,12,18 or promoter 19 or during photocatalysis for the decomposition of nitrous oxide.…”