摘要
通过溶胶凝胶法制备了纳米晶TiO2光催化剂,并采用浸渍还原法制得相应负载贵金属的TiO2.利用XRD、UV-VIS-DRS和N2吸附等方法表征了催化剂的结构和织构,同时考察了反应气氛、Pt负载量、贵金属种类、葡萄糖投加量等对葡萄糖重整产氢的影响,比较了不同分子量碳水化合物在Pt/TiO2上光催化重整产氢的效率.结果表明,贵金属修饰对TiO2的晶相、比表面积的影响并不大,但能大大提高TiO2对糖类的产氢活性.当负载Pt的质量分数为1%时,样品对葡萄糖的光催化产氢活性最大;当负载等量贵金属且质量分数均为1%时,重整葡萄糖产氢的活性由高到低的顺序为:Pt/TiO2,Pd/TiO2,Au/TiO2,Rh/TiO2,Ag/TiO2,Ru/TiO2,其中Pt/TiO2与Pd/TiO2、Ag/TiO2与Ru/TiO2的活性相近.另外发现,O2对葡萄糖光催化重整产氢有抑制作用,而N2气氛对重整产氢有促进作用.多糖重整反应研究表明,Pt/TiO2对某些糖类有良好的光催化重整产氢活性,但产氢速率却随着多糖聚合度的增加逐渐降低.葡萄糖投加量实验表明,葡萄糖初始浓度对产氢反应速率的影响符合Langmuir-Hinshelwood关系式.
Nano-TiO2 and noble metals-supported TiO2 are prepared by a sol-gel method and an impregnation-reduction technique, respectively. The structures and textures of the as-synthesized catalysts are characterized by XRD, UV-VIS-DRS spectroscopy, and N2 adsorption. The influences of the reactive atmospheres, the loaded amounts of Pt, the type of loaded metals, and the initial concentration of glucose on the glucose reforming into hydrogen are investigated. The photocatalytic hydrogen evolution activities of Pt/TiO2 for different carbohydrates are also compared. The results show that loading of noble metals can remarkably enhance the activity of TiO2 for the hydrogen evolution from an aqueous solution of glucose, although no noticeable changes in the crystal phase and BET surface area of TiO2 are observed. Pt/TiO2 shows the highest activity when mass fraction of Pt reaches 1%. In the case of 1% mass fraction of noble metal, the hydrogen evolution of glucose decreases in the order Pt/TiO2, Pd/TiO2, Au/TiO2, Rh/TiO2, Ag/TiO2, Ru/TiO2. The O2 ambience inhibits the hydrogen evolution, while N2 is favorable for the formation of hydrogen. All the carbohydrates show good hydrogen production, but the evolution rate decreases as the polymerization degree increases. The effect of the initial concentration of glucose on the reaction rate follows the kinetic model of Langmuir-Hinshelwood.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2008年第8期1044-1048,共5页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(20537010
20673020
20573020)
关键词
光催化
碳水化合物
制氢
photocatalysis
carbohydrate
hydrogen production
