Effects of ZrO₂ addition to the Au/CeO₂ and the pretreatment methods of the catalysts on the partial oxidation of methanol (POM) were investigated. ZrO₂ addition to Au/CeO₂ catalyst led to (i) formation of a Ce_0.5Zr_0.5O₂ solid solution; (ii) enhancement of lattice oxygen reducibility of the Ce_0.5Zr_0.5O₂ support; and (iii) formation of surface Au^δ+ (δ = 1 or 3) species coexisting with Au⁰ nanoparticles. Catalytic evaluation showed that the highest hydrogen selectivity was achieved over Au/Ce_0.5Zr_0.5O₂ at 270 °C. The reductive pretreatment could improve the hydrogen selectivity and methanol conversion as well. At higher reaction temperature Au^δ+ clusters in Au/Ce_0.5Zr_0.5O₂ catalyst activated the O‒H bond in the adsorbed CH₃‒O^δ−‒H^δ+ due to the interaction between Au^δ+ and O^δ−‒H^δ+ of methanol that favors the release of H⁺ proton, and thus benefits the H₂ selectivity enhancement. Some oxygen vacancies in the catalysts evidenced by XPS analysis participated in the formation of active surface oxygen species that promoted CO oxidation to CO₂ on Au⁰ nanoparticles A reaction mechanism of POM involving in the methanol surface adsorption on Au^δ+ species, O‒H bond activation, and CO oxidation on Au⁰ nanoparticles and oxygen defects was proposed.

Graphic abstract

中文翻译：

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Au / Ce 0.5 Zr 0.5 O 2催化剂，用于甲醇部分氧化制氢

的ZrO的影响₂除了在Au /的CeO ₂进行了调查，对甲醇（POM）的部分氧化的催化剂的预处理方法。向Au / CeO ₂催化剂中添加ZrO ₂导致（i）形成Ce _0.5 Zr _0.5 O ₂固溶体；（ii）增强Ce _0.5 Zr _0.5 O ₂载体的晶格氧还原性；（iii）形成与Au ⁰纳米颗粒共存的表面Auδ ⁺（δ= 1或3）物种。催化评估表明，在Au / Ce _0.5 Zr上实现了最高的氢选择性在270°C下_为0.5 O ₂。还原预处理还可以提高氢选择性和甲醇转化率。在更高的反应温度的Au ^δ+中的Au / Ce的簇_0.5的Zr _0.5 ø ₂催化剂活化在吸附的CH将O-H键₃ -O ^δ- -H ^δ+由于金之间的相互作用^δ+和O ^δ- - ħ ^δ+甲醇有利于H的释放的⁺质子，并且因此有利于ħ ₂选择性增强。在通过XPS分析证实催化剂一些氧空位参与活性表面氧物种促进CO氧化成CO的形成₂在Au ⁰纳米颗粒POM的在对Au甲醇表面吸附涉及的反应机制^δ+物种，O - H提出了键活化，CO在Au ⁰纳米颗粒上的氧化和氧缺陷的方法。

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