Zhu Juncheng, Shao Weiwei, Li Xiaodong, Jiao Xingchen, Zhu Junfa, Sun Yongfu, Xie Yi
Hefei National Laboratory for Physical Sciences at the Microscale, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China.
Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China.
J Am Chem Soc. 2021 Nov 3;143(43):18233-18241. doi: 10.1021/jacs.1c08033. Epub 2021 Oct 22.
Light-induced heat is largely neglected in traditional photocatalytic systems, especially for the thermodynamically and kinetically challenging CO reduction to C fuels. Herein, we first design asymmetric Metal-O-Metal triple-atom sites confined in phenakite to facilitate C-C coupling and employ photoinduced heat to increase molecular thermal vibration and accelerate CO reduction to C fuels. Using O-vacancy-rich ZnGeO nanobelts as prototypes, quasi in situ Raman spectra disclose the Zn-O-Ge triatomic sites are likely the reactive sites. Density functional theory calculations reveal that the asymmetric Zn-O-Ge sites could promote C-C coupling through inducing distinct charge distributions of neighboring C intermediates, whereas the created O vacancies could lower the energy barrier of the rate-determining hydrogenation step from 1.46 to 0.67 eV. Catalytic performances under different testing conditions demonstrate that light initiates the CO reduction reaction. In situ Fourier-transform infrared spectra and DO kinetic isotopic effect experiments disclose that light-induced heat kinetically triggers C-C coupling and accelerates OCCO* hydrogenation via providing abundant hydrogen species. Consequently, in a simulated air atmosphere under 0.1 W/cm illumination at 348 K, the O-vacancy-rich ZnGeO nanobelts demonstrate an acetate output of 12.7 μmol g h, a high acetate selectivity of 66.9%, a considerable CO-to-CHCOOH conversion ratio of 29.95%, and a stability of up to 220 h.
在传统光催化体系中，光致热在很大程度上被忽视了，尤其是对于将CO还原为C燃料这一在热力学和动力学上具有挑战性的过程。在此，我们首次设计了限域在硅铍石中的不对称金属-氧-金属三原子位点以促进C-C偶联，并利用光致热来增加分子热振动并加速将CO还原为C燃料的过程。以富含氧空位的ZnGeO纳米带作为原型，准原位拉曼光谱揭示了Zn-O-Ge三原子位点可能是反应位点。密度泛函理论计算表明，不对称的Zn-O-Ge位点可以通过诱导相邻C中间体的不同电荷分布来促进C-C偶联，而产生的氧空位可以将速率决定加氢步骤的能垒从1.46 eV降低到0.67 eV。不同测试条件下的催化性能表明光引发了CO还原反应。原位傅里叶变换红外光谱和DO动力学同位素效应实验表明，光致热通过提供丰富的氢物种在动力学上触发C-C偶联并加速OCCO*加氢。因此，在348 K下0.1 W/cm光照的模拟空气气氛中，富含氧空位的ZnGeO纳米带表现出12.7 μmol g h的乙酸盐产量、66.9%的高乙酸盐选择性、29.95%的可观的CO到CHCOOH转化率以及高达220 h的稳定性。
