Li Yong, Zhang Guoqing, Eugen Schwarz W H, Li Jun
Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing 100084, China.
School of Materials & Energy, Guangdong University of Technology, Guangzhou 510006, China.
Inorg Chem. 2020 May 4;59(9):6287-6300. doi: 10.1021/acs.inorgchem.0c00388. Epub 2020 Apr 20.
We have elucidated the complex reaction network of partial methanol oxidation, HCOH + O → HCO + HO, at a visible-light-activated actinide photocatalyst. The reaction inertness of C-H bonds and O═O diradicals at ambient conditions is overcome through catalysis by photoexcited uranyl units (*UO) anchored on a mesoporous silicate. The electronic ground- and excited-state energy hypersurfaces are investigated with quasirelativistic density-functional and correlated wave function approaches. Our study suggests that the molecular cluster can react on the excited energy surface due to the longevity of excited uranyl, typical for f-element compounds. The theoretically predicted energy profiles, chemical intermediates, related radicals, and product species are consistent with various experimental findings. The uranyl excitation opens various reaction pathways for the oxidation of volatile organic compounds (VOCs) by "hole-driven hydrogen transfer" (HDHT) through several exothermic steps over low activation barriers toward environmentally clean or chemically interesting products. Quantum-chemical modeling reveals the high efficiency of the uranyl photocatalysis and directs the way to further understanding and improvement of VOC degradation, chemical synthesis, and biologic photochemical interactions between uranyl and the environment.
我们已经阐明了在可见光激活的锕系光催化剂上，部分甲醇氧化反应HCOH + O → HCO + HO的复杂反应网络。通过锚定在介孔硅酸盐上的光激发铀酰单元（*UO）的催化作用，克服了环境条件下C-H键和O═O双自由基的反应惰性。利用准相对论密度泛函和相关波函数方法研究了电子基态和激发态能量超曲面。我们的研究表明，由于f元素化合物典型的激发态铀酰寿命较长，分子簇可以在激发能表面上发生反应。理论预测的能量分布、化学中间体、相关自由基和产物种类与各种实验结果一致。铀酰激发通过“空穴驱动氢转移”（HDHT）为挥发性有机化合物（VOCs）的氧化开辟了各种反应途径，通过几个放热步骤越过低活化能垒，生成环境清洁或化学上有趣的产物。量子化学建模揭示了铀酰光催化的高效率，并为进一步理解和改进VOC降解、化学合成以及铀酰与环境之间的生物光化学相互作用指明了方向。
