Zheng Kai, Wu Yang, Hu Zexun, Jiao Xingchen, Li Li, Zhao Yuan, Wang Shumin, Zhu Shan, Liu Wenxiu, Yan Wensheng, Sun Yongfu, Xie Yi
Hefei National Laboratory for Physical Sciences at Microscale, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Institute of Energy, Hefei Comprehensive National Science Center, Hefei, Anhui 230031, People's Republic of China.
Nano Lett. 2021 Dec 22;21(24):10368-10376. doi: 10.1021/acs.nanolett.1c03682. Epub 2021 Dec 13.
Selective partial photooxidation of CH into value-added chemicals under mild conditions still remains a huge bottleneck. Herein, we design positively charged metal clusters anchored on a three-dimensional porous carbon aerogel. With 0.75FeCA800-4 as an example, X-ray photoelectron spectra and Raman spectra disclose that the iron sites are positively charged. electron paramagnetic resonance spectra show that the Fe sites could donate electrons to activate CH into CH by virtue of the excited-state carbon atoms; meanwhile, they could convert HO into OH radicals under irradiation. In addition, diffuse Fourier-transform infrared spectra suggest the CHOOH obtained is derived from CH oxidation by the hydroxylation of *CH and *CHO intermediates. Consequently, 0.75FeCA800-4 displays a CHOOH selectivity of near 100% and a CHOOH evolution rate of 13.2 mmol g h, higher than those of most previously reported supported catalysts under similar conditions.
在温和条件下将CH选择性部分光氧化为增值化学品仍然是一个巨大的瓶颈。在此，我们设计了锚定在三维多孔碳气凝胶上的带正电荷的金属簇。以0.75FeCA800-4为例，X射线光电子能谱和拉曼光谱表明铁位点带正电荷。电子顺磁共振光谱表明，Fe位点可以通过激发态碳原子将电子提供给CH以将其激活为CH；同时，它们可以在辐照下将HO转化为OH自由基。此外，漫反射傅里叶变换红外光谱表明，所得的CHOOH是由CH和CHO中间体的羟基化对CH进行氧化而产生的。因此，0.75FeCA800-4显示出接近100%的CHOOH选择性和13.2 mmol g h的CHOOH生成速率，高于大多数先前报道的负载型催化剂在类似条件下的选择性和生成速率。
