The bi-functional mechanism of CH4 dry reforming over a Ni–CaO–ZrO2 catalyst: further evidence via the identification of the active sites and kinetic studies
The bi-functional mechanism of CH4 dry reforming over a Ni–CaO–ZrO2 catalyst: further evidence via the identification of the active sites and kinetic studies
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DOI：
10.1039/c3cy00153a
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发表时间：
2013-08
影响因子：
5
通讯作者：
Changzhen Wang;Nannan Sun;Min Kang;Xia Wen;N. Zhao;Fukui Xiao;Wei Wei-Wei;T. Zhao;Yuhan Sun
中科院分区：
文献类型：
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作者：
Changzhen Wang;Nannan Sun;Min Kang;Xia Wen;N. Zhao;Fukui Xiao;Wei Wei-Wei;T. Zhao;Yuhan Sun
采用N2物理吸附、程序升温还原（TPR）、H2/CO化学吸附等方法对一种具有优良甲烷干重整性能的介孔Ni-CaO-ZrO 2催化剂进行了表征。特别是，样品经过不同的处理，如煅烧，还原和不同时期的反应进行X射线衍射（XRD）和X射线光电子能谱（XPS）分析，通过其中的相结构和表面化学的变化。结果表明，在反应过程中，金属镍逐渐被氧化，并缓慢形成非化学计量比的镍碳化合物。后一种物质作为重要的中间体（甚至是活性相）发挥作用。根据这些发现进行了动力学研究，并据此建立了Langmuir-Hinshelwood模型。实验结果和动力学分析为ZrO 2基催化剂上干重整反应的双功能机理提供了新的证据。
A mesoporous Ni–CaO–ZrO2 catalyst which showed an excellent performance in the dry reforming of CH4 was thoroughly characterized by using a series of methods including N2 physical adsorption, temperature-programmed reduction (TPR), H2/CO chemisorptions, and so forth. Particularly, samples after different treatments such as calcination, reduction and different periods of reaction were subjected to X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis, by which changes in the phase structure and surface chemistry were followed. The results suggested that metallic Ni was gradually oxidized during the reaction, and a non-stoichiometric Ni–carbon compound was slowly formed. This latter species has a role as an important intermediate (or even active phase). Kinetic studies were then carried out based on these findings, according to which a Langmuir–Hinshelwood model was developed. Both the experimental results and the kinetic analysis provided novel evidence for the bi-functional mechanism of dry reforming over ZrO2-based catalysts.