Near ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) was used to study the chemical states of a range of alumina-supported monometallic Pd and bimetallic Pd–Pt nanocatalysts, under methane oxidation conditions. It has been suggested before that for optimal complete methane oxidation, palladium needs to be in an oxidised state. These experiments, combining NAP-XPS with a broad range of characterisation techniques, demonstrate a clear link between Pt presence, Pd oxidation, and catalyst activity under stoichiometric reaction conditions. Under oxygen-rich conditions this behaviour is less clear, as all of the palladium tends to be oxidised, but there are still benefits to the addition of Pt in place of Pd for complete oxidation of methane.

在甲烷氧化条件下，采用近环境压力X射线光电子能谱（NAP-XPS）研究了一系列氧化铝负载的单金属Pd和双金属Pd-Pt纳米催化剂的化学状态。之前已经提出，为了最佳地完全甲烷氧化，钯需要处于氧化态。这些实验结合了NAP-XPS和广泛的表征技术，证明了在化学计量反应条件下Pt的存在，Pd的氧化和催化剂活性之间的明确联系。在富氧条件下，这种行为不太清楚，因为所有钯都倾向于被氧化，但是添加Pt代替Pd对于甲烷的完全氧化仍然有好处。