Modifying the Surface of γ‐Al₂O₃with Y₂Sn₂O₇Pyrochlore: Monolayer Dispersion Behaviour of Composite Oxides

Abstract

To investigate the dispersion behaviour of composite oxides on supports, and to obtain better supports for Pd for CO oxidation, a series of Y Sn O /Al O composite oxides with different Y Sn O loadings were prepared by a deposition-precipitation method. XRD and X-ray photoelectron spectroscopic extrapolation methods revealed that, similar to single-component metal oxides, composite oxides can also disperse spontaneously on support surfaces to form a monolayer with a certain capacity. The monolayer dispersion capacity/threshold for Y Sn O on the surface of γ-Al O is 0.109 mmol per 100 m γ-Al O , corresponding to 7.2 wt % Y Sn O loading. This is the first work to demonstrate monolayer dispersion of a composite oxide on a support. After combining Y Sn O with γ-Al O , active oxygen species can be introduced onto the catalyst surfaces. Thus, the interaction between Pd and the support is strengthened, the dispersion of Pd is improved in comparison with the single-component Y Sn O support, and a synergistic effect is induced between Pd and the composite support, which is beneficial to catalyst activity. By tuning the γ-Al O surface with different amounts of pyrochlore Y Sn O , CO oxidation activity on 1 % Pd/Y Sn O /Al O was improved. These findings may provide new insights into the design and preparation of effective supported noble metal catalysts with lower contents of noble metals.

Constructing La2B2O7 (B = Ti, Zr, Ce) Compounds with Three Typical Crystalline Phases for the Oxidative Coupling of Methane: The Effect of Phase Structures, Superoxide Anions, and Alkalinity on the Reactivity

“…Therefore, they have been investigated as functional materials for various applications such as magnetic, electrical, and optical materials. − The investigations on their catalytic properties are much less documented. Our former studies have demonstrated that A 2 B 2 O 7 compounds with different A- or/and B-site compositions displayed very good performance for several high-temperature reactions, including methane reforming and OCM reaction. − It has been substantiated that an effective OCM catalyst usually possesses surface electrophilic oxygen sites and also has certain surface alkalinity. ,,, A typical A 2 B 2 O 7 compound containing a trivalent rare-earth A-site can provide surface alkalinity, which matches mostly the requirement of a good OCM catalyst, together with its mobile oxygen species. Therefore, our former work has testified that a La 2 Ce 2 O 7 catalyst displays very good performance for OCM reaction, especially in the low-temperature region .…”

Lattice capacity-dependent activity for CO2 methanation: crafting Ni/CeO2 catalysts with outstanding performance at low temperatures

“…2a and b), all Ca 2+ cations were incorporated into the lattice structure of CeO 2 , thereby eluding detection through XRD analysis. 43,44…”

Preparation of Monolayer Dispersed Fe/Attapulgite Desulfurizer and Its Desulfurization Performance at Low Temperature

“…According to the monolayer dispersion thresholds theory, [13] the characteristics of active components will not appear in the XRD pattern when loads of active components are low; when loads of active components exceed the monolayer dispersion threshold, obvious diffraction peaks of active components will appear. Based on XRD patterns, the extrapolation can be used to determine the monolayer dispersion threshold of metal oxides on the carrier [14] . ATP was taken as the internal standard, the ratio of the peak intensity of Fe 2 O 3 and the peak intensity of ATP was plotted, and the results were shown in Figure 2.…”

“…Based on XRD patterns, the extrapolation can be used to determine the monolayer dispersion threshold of metal oxides on the carrier. [14] ATP was taken as the internal standard, the ratio of the peak intensity of Fe 2 O 3 and the peak intensity of ATP was plotted, and the results were shown in Figure 2. The fitted linear equation was y = 215.25x-61.89, the point where the line intersects the X-axis was the inflection point, which indicated that the crystal phase of Fe 2 O 3 just began to…”