溶胶-凝胶法制备Ni_2V_2O_7的丙烷氧化脱氢催化性能

以柠檬酸为配位剂,溶胶-凝胶法制备Ni2V2O7,采用X射线衍射、氮气物理吸附、电感耦合等离子体原子发射光谱、氢气程序升温还原、X射线光电子能谱和透射电子显微镜等技术对催化剂进行了表征.通过差热-热重分析,考察干凝胶分解为Ni2V2O7的温度以及分解过程的热效应并研究了不同焙烧温度与Ni2V2O7的形成、晶化程度之间的关系以及对丙烷氧化脱氢(ODH)制丙烯反应催化性能的影响.     

An Interactive Approach for Choosing the Best of a Set of Alternatives

In this paper we address the problem of choosing the most preferred alternative among a large number of alternatives where each alternative is defined by multiple criteria. We assume that the decision maker has a quasiconcave utility function. We develop an exact approach that combines the ideas that have appeared in the literature regarding the use of different types of dummy alternatives in conjunction with real alternatives. Our experimental results indicate that the new approach is comparable to leading existing approaches.     

NiO_x/介孔杭锦2~#土的制备及其对苯羟基化光催化性能研究

以沉积沉淀法制备Ni Ox/介孔杭锦2#土催化剂,通过X射线粉末衍射,比表面积及孔结构分析,固体紫外可见漫反射等手段对催化剂进行了表征.以H2O2为氧化剂,在汞灯照射下,研究其对光催化苯直接羟基化反应的催化性能,并探讨了镍的负载量,光源等因素对苯直接氧化制苯酚反应的影响.结果表明,随着镍含量的增加,苯酚的选择性和产率先增大后减小.在优化的反应条件下,苯酚的选择性和产率分别为93%和为56%.     

Strong Photoelectric Properties of Mn-Based Seleniumstannates with Alkali Metals as Structure-Directing Agents

In recent years, chalcogenides have received a lot of attention because of their potential applications as photoelectric material. This work describes the synthesis of the quaternary seleniumstannates Cs₂MnSnSe₄ ( 1 ) and Rb₂MnSnSe₄ ( 2 ) using solvothermal methods. The structure of compound 1 consists of charge-balanced Cs⁺ cation and one-dimensional (1D) anion [MnSnSe₄]_n²⁻ chain. Compound 2 possesses a unique two-dimensional (2D) anion [MnSnSe₄]_n²⁻ layer. It is noteworthy that the compounds exhibit a strong photocurrent response (ca. 45 μA/cm² ( 1 ), ca. 80 μA/cm² ( 2 )). Moreover, methylene blue (MB) was investigated for its photocatalytic degradation properties. In order to better understand the relationship between optical properties and electronic structure, a theoretical study was conducted.