The redox properties of supported Pd catalysts can directly affect their methane combustion activity. Here, the effect of the support on methane combustion was elucidated using Pd nanoparticles supported on various metal oxides (θ-Al₂O₃, γ-Al₂O₃, ZrO₂, CeO₂, MgO, La₂O₃, TiO₂, SnO₂, and Nb₂O₅). To eliminate the effect of Pd particle size and morphology, uniform Pd particles were synthesized in the liquid phase. Interestingly, the methane combustion activity formed a volcano plot when plotted against the oxide formation enthalpy (Δ_fH_M-O°) of the support. Combining X-ray photoelectron spectroscopy and scanning transmission electron microscopy–electron energy loss spectroscopy, the structure of the Pd nanoparticles on the support in an oxidizing atmosphere was identified. Pd particles on θ-Al₂O₃, γ-Al₂O₃, ZrO₂, and CeO₂ with moderate Δ_fH_M-O° adopted a metal-core–oxide-shell structure and showed the highest activities for methane combustion. In contrast, completely oxidized Pd particles were present on MgO and La₂O₃, which have lower Δ_fH_M-O° and were not very active. Pd metal particles on TiO₂, SnO₂, and Nb₂O₅ with higher Δ_fH_M-O° were not effective catalysts for methane combustion.

中文翻译：

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利用金属-载体相互作用来调节负载型甲烷燃烧钯催化剂的氧化还原性能

负载型钯催化剂的氧化还原性质可以直接影响其甲烷燃烧活性。此处，阐明在甲烷燃烧的载体的效果使用Pd纳米颗粒负载于各种金属氧化物（θ-Al系₂ ö ₃，γ-Al系₂ ö ₃，的ZrO ₂，的CeO ₂，MgO的，拉₂ ö ₃，二氧化钛₂，SnO ₂和Nb ₂ O ₅）。为了消除Pd粒径和形态的影响，在液相中合成了均匀的Pd粒子。有趣的是，当针对氧化物形成焓（Δ_f H _M-O °）的支撑。结合X射线光电子能谱和扫描透射电子显微镜–电子能量损失谱，鉴定了在氧化气氛中载体上Pd纳米颗粒的结构。上θ-Al系Pd粒子₂ ö ₃，γ-Al系₂ ö ₃，的ZrO ₂，和的CeO ₂中度Δ _˚F ħ _M-O °采用金属芯-氧化物-壳结构和表现出对甲烷燃烧的最高活动。与此相反，完全氧化的Pd粒子存在对MgO和La ₂ ö ₃，其具有较低的Δ _˚F ħ_MO °并不太活跃。在TiO的Pd金属颗粒₂，的SnO ₂和Nb ₂ ö ₅具有更高的Δ _˚F ħ _M-O °不是为甲烷燃烧有效的催化剂。