Ke Jingwen, Chi Mingfang, Zhao Jiankang, Liu Yan, Wang Ruyang, Fan Kaiyuan, Zhou Yuxuan, Xi Zhikai, Kong Xiangdong, Li Hongliang, Zeng Jie, Geng Zhigang
Hefei National Research Center for Physical Sciences at the Microscale, Key Laboratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of Sciences, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
School of Chemistry & Chemical Engineering, Anhui University of Technology, Ma'anshan, Anhui 243002, P. R. China.
J Am Chem Soc. 2023 Apr 26;145(16):9104-9111. doi: 10.1021/jacs.3c00660. Epub 2023 Mar 21.
For the electrooxidation of propylene into 1,2-propylene glycol (PG), the process involves two key steps of the generation of *OH and the transfer of *OH to the C═C bond in propylene. The strong *OH binding energy ((*OH)) favors the dissociation of HO into *OH, whereas the transfer of *OH to propylene will be impeded. The scaling relationship of the (*OH) plays a key role in affecting the catalytic performance toward propylene electrooxidation. Herein, we adopt an immobilized Ag pyrazole molecular catalyst (denoted as AgPz) as the electrocatalyst. The pyrrolic N-H in AgPz could undergo deprotonation to form pyrrolic N (denoted as AgPz-H), which can be protonated reversibly. During propylene electrooxidation, the strong (*OH) on AgPz favors the dissociation of HO into *OH. Subsequently, the AgPz transforms into AgPz-H that possesses weak (*OH), benefiting to the further combination of *OH and propylene. The dynamically reversible interconversion between AgPz and AgPz-H accompanied by changeable (*OH) breaks the scaling relationship, thus greatly lowering the reaction barrier. At 2.0 V versus Ag/AgCl electrode, AgPz achieves a remarkable yield rate of 288.9 mmol g h, which is more than one order of magnitude higher than the highest value ever reported.
对于将丙烯电氧化为1,2 - 丙二醇（PG）的过程，该过程涉及生成OH以及OH转移至丙烯中的C═C键这两个关键步骤。强的OH结合能（（OH））有利于HO解离为OH，然而OH向丙烯的转移会受到阻碍。（*OH）的比例关系在影响丙烯电氧化的催化性能方面起着关键作用。在此，我们采用固定化的Ag吡唑分子催化剂（表示为AgPz）作为电催化剂。AgPz中的吡咯N - H可发生去质子化形成吡咯N（表示为AgPz - H），其可可逆地质子化。在丙烯电氧化过程中，AgPz上强的（OH）有利于HO解离为OH。随后，AgPz转变为具有弱（OH）的AgPz - H，有利于OH与丙烯的进一步结合。AgPz和AgPz - H之间伴随着可变（*OH）的动态可逆相互转化打破了比例关系，从而极大地降低了反应势垒。相对于Ag/AgCl电极在2.0 V时，AgPz实现了288.9 mmol g⁻¹ h⁻¹的显著产率，这比以往报道的最高值高出一个多数量级。
