Methane combustion over Pd/CoAl2O4/Al2O3 catalysts prepared by galvanic deposition
Methane combustion over Pd/CoAl2O4/Al2O3 catalysts prepared by galvanic deposition
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DOI：
10.1039/c7ra06150a
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发表时间：
2017-01-01
期刊：
影响因子：
3.9
通讯作者：
Satsuma, Atsushi
中科院分区：
文献类型：
--
作者：
Mahara, Yuji;Tojo, Takumi;Satsuma, Atsushi
采用电沉积（GD）方法合成了 Pd/CoAl2O4/Al2O3 甲烷燃烧催化剂（PdCoAl-GD）。这种 PdCoAl-GD 催化剂表现出比传统 Pd/Al2O3 更高的活性和周转频率 (TOF)。根据X射线衍射（XRD）、X射线吸收精细结构（XAFS）和扫描透射电子显微镜（STEM）测量，PdCoAl-GD由负载在γ-Al2O3上的CoAl2O4相和分散在CoAl2O4上的尺寸为2-7 nm的Pd纳米颗粒组成。 Operando Pd K 边缘 XAFS 测量表明，PdCoAl-GD 中的 Pd 在低温下被氧化成高活性的甲烷燃烧 PdO 物质。当 PdO 最初存在于催化剂上时，PdCoAl-GD 也表现出高活性（起燃测试）。 PdCoAl-GD 上的甲烷程序升温反应 (CH4-TPR) 测量表明 PdO 在低温下被 CH4 还原。本文使用的 GD 方法获得了对 C-H 活化有效的 PdO 物质。
Pd/CoAl2O4/Al2O3 methane combustion catalysts were synthesized using a galvanic deposition (GD) method (PdCoAl-GD). This PdCoAl-GD catalyst showed higher activities and turnover frequencies (TOFs) than conventional Pd/Al2O3. According to X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and scanning transmission electron microscopy (STEM) measurements, PdCoAl-GD was composed of a CoAl2O4 phase supported on gamma-Al2O3 and dispersed Pd nanoparticles of 2-7 nm in size on CoAl2O4. Operando Pd K-edge XAFS measurements indicated that the Pd in PdCoAl-GD was oxidized to highly active methane combustion PdO species at low temperatures. PdCoAl-GD also showed high activity (light-off tests) when PdO was initially present on the catalysts. Methane temperature-programmed reaction (CH4-TPR) measurements on PdCoAl-GD revealed that PdO was reduced by CH4 at low temperatures. The GD method used herein achieved PdO species that were effective for C-H activation.