Ye Gan, Yang Zhaohan, Wan Lulu, Shi Guangming, Chang Yuying, Zhang Qiuli
School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Dalton Trans. 2023 Nov 7;52(43):15968-15973. doi: 10.1039/d3dt02719h.
Insights into the relationship between the crystal structure and activity of metal-organic frameworks (MOFs) are meaningful to investigate the potential properties of pristine MOFs for targeted catalytic reactions. Herein, we develop a high-efficiency method for boosting the oxidative desulfurization (ODS) activity of Ti-MOF in the presence of H. The ODS activity of pristine Ti-MOF prepared a solvothermal approach is very poor at a low reaction temperature but can be enhanced in the presence of H. Ti-MOF in the presence of H shows ultrahigh ODS activity that can eliminate 1000 ppm sulfur after 7 min at 30 °C with no catalytic activity loss after recycling 11 times. The turnover frequency value reaches 12.4 h at 30 °C, surpassing all the previously reported Ti-MOFs as ODS catalysts even at high temperatures. Characterization and quenching experimental results indicate that more uncoordinated Ti sites can be formed from slight damage to the structure of Ti-MOF during the catalytic reaction, and such exposed Ti sites can easily react with H and HO to form Ti-hydroperoxo active species that determine the upgradation of ODS activity. This work provides a significant way to upgrade the catalytic activity of pristine Ti-MOFs for future application.
深入了解金属有机框架（MOF）的晶体结构与活性之间的关系，对于研究原始MOF在目标催化反应中的潜在性能具有重要意义。在此，我们开发了一种高效方法，用于在氢气存在下提高Ti-MOF的氧化脱硫（ODS）活性。通过溶剂热法制备的原始Ti-MOF在低温下的ODS活性非常低，但在氢气存在下可以得到增强。在氢气存在下的Ti-MOF表现出超高的ODS活性，在30°C下7分钟后可去除1000 ppm的硫，循环使用11次后催化活性无损失。在30°C下，周转频率值达到12.4 h，即使在高温下也超过了所有先前报道的作为ODS催化剂的Ti-MOF。表征和猝灭实验结果表明，在催化反应过程中，Ti-MOF结构的轻微破坏会形成更多未配位的Ti位点，这些暴露的Ti位点可以很容易地与氢气和过氧化氢反应形成钛过氧活性物种，从而决定了ODS活性的提升。这项工作为未来应用中提升原始Ti-MOF的催化活性提供了一条重要途径。
