摘要
Catalytic oxidation desulfurization(CODS)technology has shown great promise for diesel desulfurization by virtue of its low cost,mild reaction conditions,and superior desulfurization performance.Herein,a series of FeMoO_(x)/LaTiO_(y)-z samples with diverse Fe/Mo ratios were prepared via a facile citric acid-assisted method.The impact of Fe incorporation on the dispersion and surface elemental states of Mo species,as well as oxygen species content of the synthesized FeMoO_(x)/LaTiO_(y)-z catalysts were systematically characterized using TEM,BET,UV-vis DRS,XPS,XANES,and reaction kinetics,and their CODS performances were examined for 4,6-DMDBT removal.Experimental results demonstrated that Fe/Mo ratio significantly affected the Ti−O bond strength,surface dispersion and electronic structure of Mo O_(2)species on FeMoO_(x)/LaTiO_(y)-z catalysts.FeMoO_(x)/LaTiO_(y)-2 catalyst showed outstanding cycling durability and the best CODS performance with almost 100%removal of 4,6-DMDBT from model oil within 75 min due to its proper MoO3 dispersion,optimal redox property,and the most oxygen vacancy concentration.Nevertheless,further enhancing Fe content led to the increased dispersion of Mo species,while the decrease active Mo species as well as the increase of steric effect for 4,6-DMDBT accessing to the catalytic reactive sites considerably increase the apparent activation energy of FeMoO_(x)/LaTiO_(y)-z(z>2)catalysts during the CODS process,thereby seriously suppressing their CODS performances.Moreover,Radical trapping experiments reveal that the·,generated by the activation of O_(2)at the active sites,catalytic oxidized 4,6-DMDBT to the product of 4,6-DMDBTO_(2),thereby enabling both deep desulfurization and recovery of high-value 4,6-DMDBTO_(2).These findings offer an alternative strategy to achieve ultra deep desulfurization as well as separate and recover high economic value sulfone substances from diesel.
催化氧化脱硫(CODS)技术因其成本低廉、反应条件温和及优异的脱硫性能,在柴油深度脱硫领域展现出广阔应用前景。本研究通过简易柠檬酸辅助法制备了不同Mo/Fe物质的量比的FeMoO_(x)/LaTiO_(y)-z催化剂,综合运用TEM、BET、UV-vis DRS、XPS、XANES及反应动力学等手段系统研究了Fe掺杂对催化剂中Mo物种分散度、表面元素化学态及氧物种含量的调控机制,并以4,6-二甲基二苯并噻吩(4,6-DMDBT)为模型化合物评估其CODS性能。实验结果表明,Mo/Fe比对FeMoO_(x)/LaTiO_(y)-z催化剂中Ti-O键强度、Mo物种表面分散度及电子结构具有显著影响。其中,FeMoO_(x)/LaTiO_(y)-2催化剂因具有适宜的MoO_(3)分散度、优化的氧化还原特性及最高的氧空位浓度,在75 min内即可实现模型油中4,6-DMDBT的近乎完全脱除,同时展现出优异的循环稳定性。过高的Fe含量(z>2)虽可提升Mo物种分散度,但会导致活性Mo物种减少以及4,6-DMDBT分子接近催化剂活性位点的空间位阻效应增强,显著提高了表观活化能,从而严重抑制其CODS性能。自由基捕获实验证实,活性位点活化O_(2)生成的·O_(2)^(-)可将4,6-DMDBT选择性氧化为高附加值的4,6-DMDBTO_(2),实现了深度脱硫与高值硫氧化合物的同步回收。本工作为柴油超深度脱硫及高经济价值砜类化合物的分离回收提供了新策略。
出处
《燃料化学学报(中英文)》
北大核心
2025年第8期1255-1268,共14页
Journal of Fuel Chemistry and Technology
基金
supported by the Natural Science Foundation of Guangdong Province(2024A1515010908,2025A1515011103)
Opening Project of Hubei Key Laboratory of Plasma Chemistry and Advanced Materials(2024P11)
Postdoctoral Fellowship Program of CPSF(GZC20233104)
National Natural Science Foundation of China(22202087)
Opening Project of Hubei Key Laboratory of Biomass Fibers and Eco-Dyeing&Finishing(STRZ202418)。
