Mo/γ-Al_2O_3表面H_2的吸附性能

H_2 Adsorption on the Surface of Mo/γ-Al_2O_3 Catalyst

利用H2与探针分子吸附的原位红外光谱技术,研究了担载Mo的质量分数为15%的Mo/-γAl2O3催化剂表面的H2吸附。结果表明,还原态的Mo/-γAl2O3催化剂表面可以形成多种配位不饱和Mo中心(Mo(CUS)),H2易在由桥式Mo—O—Mo键还原形成的Mo(CUS)上吸附。在323 K下,H2主要以质子形式可逆吸附在Mo金属的表面;在较高温度下(573 K),H2解离吸附在Mo(CUS)上,产生活化氢,使催化剂表面吸附物种发生加氢反应。证实H2与探针分子的交替吸附及共吸附的实验可以有效地提供Mo/-γAl2O3催化剂表面H2吸附的信息。

H2 adsorption properties of hydrogenation catalyst were studied by analyzing the insitu FT-IR the spectra of H2 and probe molecules adsorbed on Mo/γ-Al2O3 with 15% mass fraction of Mo. The results indicated that there were several unsaturated sites on the surface of reduced Mo/γ-Al2O3, and H2 could be easily adsorbed on coordinated unsaturated Mo sites （Mo（CUS）） formed by reduction of Mo-O-Mo in different coordinated Mo sites. At 323K, H2 was mainly adsorbed on surface of the catalyst reversibly in the form of proton; at 573K, H2 could dissolved on Mo（CUS）, forming the concomitant active hydrogen, by which the adsorbed species could be hydrogenated. H2 adsorption properties on catalyst could be obtained by using coadsorption and alternate adsorption of H2 and the probe molecules on the surface of catalyst.