非均相多钼氧簇/硅藻土催化氧化碘离子研究

采用浸渍法制备keggin型多钼氧簇/改性硅藻土(PMoO/Dia)催化剂。分别采用FT-IR、XRD、BET、SEM和碘离子选择电极来测试并研究催化剂结构,表面形貌和碘离子催化性能。利用分子力学和量子化学方法对PMoO在Di和Dia表面的吸附进行计算模拟。研究结果显示:负载后的PMoO高度有序分散在Dia表面上且未改变其原有的Keggin结构;在加有0.5 g的7%PMoO/Dia催化剂的反应体系中反应8 min后碘离子的转化率为99.7%,反应速率达到了2.25×10^-5 mol/(L·s),与空白相比,PMoO/Dia的催化效果提高2.25×10^3倍;PMoO以物理吸附和化学吸附两种方式吸附在Di和Dia表面,Dia表面的铵基增加了PMoO与Dia之间的静电吸附和化学吸附作用力,同时降低了PMoO/Dia的前线轨道能级。催化剂重复使用10次以后仍保持着良好的催化性能,重复性好,无过氧化,具有较好的应用前景。

Study on heterogeneous catalytic oxidation of iodide with PMoO/Dia

A keggin-type poly-molybdenum cluster/modified diatomaceous earth(PMoO/Dia) catalyst was prepared by impregnation. FT-IR, XRD, BET, SEM and iodide ion selective electrodes were used to test and study the catalyst structure, surface morphology and iodide catalytic performance. Molecular mechanics and quantum chemistry methods were used to simulate the adsorption of PMoO on Di and Dia surfaces. The results show that the loaded PMoO was highly dispersed on the Dia surface without changing its original Keggin structure. The conversion of iodide ion after 8 minutes of reaction in a reaction system with 0.5 g of 7% PMoO/Dia catalyst reached 99.7% and the reaction rate reached 2.25×10^-5 mol/(L·s). Compared with the blank, the catalytic effect of PMoO/Dia increased by 2.25×10^3 times. PMoO was physically adsorbed and chemisorbed on the surface of Di and Dia. The ammonium group on the surface of Dia increased the electrostatic adsorption and chemisorption between PMoO and Dia, and reduced the frontal orbital energy level of PMoO/Dia. After repeated use of the catalyst for 10 times, it still maintained good catalytic performance, good repeatability, no peroxidation, and had a good application prospect.