碳化钼和氮化钼作为氨分解催化剂的实验和理论研究,Journal of the American Chemical Society

当前位置： X-MOL 学术 › J. Am. Chem. Soc. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

碳化钼和氮化钼作为氨分解催化剂的实验和理论研究
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2013-02-21 , DOI: 10.1021/ja309734u
Weiqing Zheng ₁ , Thomas P. Cotter ₁ , Payam Kaghazchi ₂ , Timo Jacob ₂ , Benjamin Frank ₁ , Klaus Schlichte ₃ , Wei Zhang ₁ , Dang Sheng Su _{1,

4} , Ferdi Schüth ₃ , Robert Schlögl ₁

Affiliation

通过程序升温还原-渗碳方法制备的高表面积碳化钼催化剂可以通过氨的催化分解产生恒定的无 CO(x) H2。新鲜和使用过的催化剂在不同阶段通过 N2 吸附/解吸、粉末 X 射线衍射、扫描和透射电子显微镜以及电子能量损失光谱进行表征。在反应过程中观察到的高表面积碳化物的失活（在前 15 小时内）归因于由于碳化物在反应条件下的氮化导致比表面积的显着降低。理论计算证实 N 原子倾向于占据次表面位置，导致在 NH3 气氛下形成氮化物。相对较高的反应速率（30 mmol/((g of cat. ) min)) 观察到的 NH3 催化分解归因于在碳化钼和氮化钼样品中观察到的高能量位点（双晶界、堆垛层错、台阶和缺陷）。与先前报道的基于钼的催化剂相比，这些位点在合成材料中的普遍性导致更高的 H2 产率。

"点击查看英文标题和摘要"

Experimental and Theoretical Investigation of Molybdenum Carbide and Nitride as Catalysts for Ammonia Decomposition

Constant CO(x)-free H2 production from the catalytic decomposition of ammonia could be achieved over a high-surface-area molybdenum carbide catalyst prepared by a temperature-programmed reduction-carburization method. The fresh and used catalyst was characterized by N2 adsorption/desorption, powder X-ray diffraction, scanning and transmission electron microscopy, and electron energy-loss spectroscopy at different stages. Observed deactivation (in the first 15 h) of the high-surface-area carbide during the reaction was ascribed to considerable reduction of the specific surface area due to nitridation of the carbide under the reaction conditions. Theoretical calculations confirm that the N atoms tend to occupy subsurface sites, leading to the formation of nitride under an NH3 atmosphere. The relatively high rate of reaction (30 mmol/((g of cat.) min)) observed for the catalytic decomposition of NH3 is ascribed to highly energetic sites (twin boundaries, stacking faults, steps, and defects) which are observed in both the molybdenum carbide and nitride samples. The prevalence of such sites in the as-synthesized material results in a much higher H2 production rate in comparison with that for previously reported Mo-based catalysts.

更新日期：2013-02-21

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南