CuWO4/SBA-15催化剂的制备及其光催化氧化脱硫性能

以CuWO_4为活性组分、SBA-15介孔分子筛为载体,制备CuWO_4/SBA-15催化剂,利用XRD、N_2吸附-脱附、FT-IR、UV-vis、SEM、EDS和TEM对催化剂进行表征分析;以二苯并噻吩(DBT)的十二烷溶液为模拟油,研究了CuWO_4/SBA-15的光催化氧化脱硫(PODS)性能。结果表明,CuWO_4/SBA-15保持了载体高度有序的二维六方介孔结构,活性组分分布均匀,且随负载量增加,其比表面积、孔径和孔容依次减小。与CuWO_4相比,CuWO_4/SBA-15的UV-vis吸收边界蓝移,禁带宽度增加。以二苯并噻吩(DBT)的十二烷溶液为模拟油,评价催化剂的光催化氧化脱硫(PODS)性能。当CuWO_4与SiO_2质量比为0.07,催化剂用量为3%,O/S物质的量比为10∶1,剂油体积比为1∶1,光照反应100 min时,催化剂脱硫率最高,可达到81.5%,明显高于CuWO_4,催化剂重复使用六次后,活性没有明显下降。在PODS反应过程中,·OH和h~+是反应的主要活性物种。

Preparation of the CuWO4/SBA-15 catalyst and its performance in the photocatalytic oxidation desulfurization

The CuWO₄/SBA-15 catalyst was prepared with CuWO₄ as the active composite and mesoporous SBA-15 molecular sieve as the support and characterized by XRD, N₂ adsorption and desorption, FT-IR, UV-vis, SEM, EDS and TEM; the performance of CuWO₄/SBA-15 catalyst in the photocatalytic oxidation desulfurization (PODS) was investigated by using the dodecane solution of dibenzothiophene (DBT) as the model fuel. The results show that the CuWO₄/SBA-15 catalyst can maintain the two-dimensional hexagonal mesoporous structure of the support and the active component is evenly distributed on the support; the surface area, pore size and pore volume of the CuWO₄/SBA-15 catalyst decrease with an increase in the amount of active component. Compared with CuWO₄, the CuWO₄/SBA-15 catalyst displays a blue shift in absorption boundary of UV-vis spectra and an increase of the band gap. With a CuWO₄/SiO₂ mass ratio of 0.07, catalyst mass percentage of 3% in the model fuel, O/S molar ratio of 10:1, and extractant/oil volume ratio of 1:1, the desulfurization rate reaches 81.5% by carrying out the PODS reaction under light for 100 min, which is obviously higher than that over CuWO₄; moreover, no obvious decrease of catalytic activity for CuWO₄/SBA-15 was observed after 6 runs of PODS. It is proposed that ·OH and h⁺ are the main reactive intermediates in PODS.