摘要
以正硅酸乙酯(TEOS)为硅源,采用溶胶-凝胶法制备一系列非均相多钼氧簇催化剂(PMoO/SiO2)。通过FT-IR、XRD、SEM等对其结构加以表征。以过氧化氢为氧化剂、PMoO/SiO2为催化剂,研究PMoO/SiO2的负载量、反应温度、pH对催化活性的影响,利用计算机模拟揭示多钼氧簇与二氧化硅之间的相互作用。研究表明:催化剂PMoO/SiO2在负载量为25%、反应温度45℃、pH=1.4条件下碘离子的氧化反应速率为9.25×10-5mol/(L*s),与未添加催化剂相比,PMoO/SiO2的催化效果提高6.85×103倍。PMoO倾向于物理吸附在不定形SiO2的富Si面,同时以形成O-H键和O-Si键的形式发生化学相互作用,使得电子从不定形SiO2向PMoO表面转移,发生协同催化作用。催化剂在循环使用十次之后催化碘离子转化率仍高达86.5%,循环使用性好,无过氧化,具有较好的工业应用前景。
A series of heterogeneous polymolybdenum oxide cluster catalysts(PMoO/SiO2)were prepared by sol-gel method using tetraethyl orthosilicate TEOS as silicon source.The structure was characterized by FT-IR,XRD,SEM,and the like.The effects of PMoO/SiO2 loading,reaction temperature and pH on the catalytic activity were investigated by using hydrogen peroxide as oxidant and PMoO/SiO2 as catalyst.and the interaction between molybdenum oxygen clusters and silica was revealed by theoretical simulation.The results show that there is not only physical adsorption but also chemical adsorption between polymolybdenum oxygen clusters and silicon dioxide to enhance their stability.The research shows that the catalyst PMoO/SiO2 has an iodide ion oxidation rate of 9.25×10^-5 mol/(Ls)under the conditions of 25%loading,reaction temperature 45℃and pH=1.4,The catalytic effect of PMoO/SiO2 was improved by 6.85×10^3 times compared with the catalyst without addition.PMoO tends to physically adsorb on Si rich surface of amorphous SiO2,and at the same time,chemical interaction takes place in the form of O-H bond and O-Si bond,so that electrons transfer from amorphous SiO2 to the surface of PMoO and synergistic catalysis takes place.he catalytic iodide ion conversion rate is still as high as 86.5%after the catalyst is used for 10 times.,which has good recycling performance and no peroxide,and has a good industrial application prospect.
作者
蔡丽丽
郭军
李文飞
张丹
秦军
CAI Li-li;GUO Jun;LI Wen-fei;ZHANG Dan;QIN Jun(School of Chemistry and Materials Science,Normal University,Guizhou Guiyang 550001,China;State Key Laboratory of Efficient Utilization for Low Grade Phosphate Rock and Its Associated Resources,Guiyang 550014,China;Key laboratory of karst environment and geological hazards,ministry of land and resources,guizhou university,Guiyang 550025,China)
出处
《化学研究与应用》
CAS
CSCD
北大核心
2019年第7期1274-1283,共10页
Chemical Research and Application
基金
国家自然科学基金项目(21862005)资助
贵州省科技厅计划项目(黔科合LH字[2017]7336资助
黔合基础项目[2019]1457)资助
贵州省教育厅青年科技人才成长项目(黔教合KY字[2018]126)资助
中低品位磷矿及其共伴生资源高效利用国家重点实验室开放课题(WFKF2017-03)资助
关键词
多钼氧簇
二氧化硅
碘离子
氧化
非均相催化
polymolybdenum oxygen cluster
silicon dioxide
iodide ion
oxidation
heterogeneous catalysis
