Yin Shi, Bernstein Elliot R
Department of Chemistry, NSF ERC for Extreme Ultraviolet Science and Technology, Colorado State University , Fort Collins, Colorado 80523, United States.
J Phys Chem Lett. 2016 May 5;7(9):1709-16. doi: 10.1021/acs.jpclett.6b00541. Epub 2016 Apr 25.
A photo excitation fast flow reactor coupled with a single-photon ionization (118 nm, 10.5 eV) time-of-flight mass spectrometry (TOFMS) instrument is used to investigate reactions of neutral MnmOn clusters with C2H4 under visible (532 nm) light irradiation. Association products Mn2O5(C2H4) and Mn3O6,7(C2H4) are observed without irradiation. Under light irradiation, the Mn2O5(C2H4) TOFMS feature decreases, and a new species, Mn2O5H2, is observed. This light-activated reaction suggests that the visible radiation can induce the chemistry, Mn2O5 + C2H4 + hv(532 nm) → Mn2O5*(C2H4) → Mn2O5H2 + C2H2. High barriers (0.67 and 0.59 eV) are obtained on the ground-state potential energy surface (PES); the reaction is barrierless and thermodynamically favorable on the first excited-state PES, as performed by time-dependent density functional theory calculations. The calculational and experimental results suggest that Mn2O5-like structures on manganese oxide surfaces are the appropriate active catalytic sites for visible light photocatalysis of ethylene dehydrogenation.
一台与单光子电离（118纳米，10.5电子伏特）飞行时间质谱仪（TOFMS）联用的光激发快速流动反应器，用于研究中性MnmOn团簇与C2H4在可见光（532纳米）照射下的反应。在无照射情况下观察到缔合产物Mn2O5(C2H4)和Mn3O6,7(C2H4)。在光照射下，Mn2O5(C2H4)的TOFMS特征峰降低，并观察到一个新物种Mn2O5H2。这种光活化反应表明，可见光辐射可引发化学反应，Mn2O5 + C2H4 + hv(532纳米) → Mn2O5*(C2H4) → Mn2O5H2 + C2H2。通过含时密度泛函理论计算得出，在基态势能面（PES）上存在高势垒（0.67和0.59电子伏特）；而在第一激发态势能面上，该反应无势垒且在热力学上有利。计算和实验结果表明，氧化锰表面的类Mn2O5结构是乙烯脱氢可见光光催化的合适活性催化位点。
