Lin Sheng-Chih, Chang Chun-Chih, Chiu Shih-Yun, Pai Hsiao-Tien, Liao Tzu-Yu, Hsu Chia-Shuo, Chiang Wei-Hung, Tsai Ming-Kang, Chen Hao Ming
Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
Department of Chemical and Material Engineering, Chinese Culture University, Taipei, 11114, Taiwan.
Nat Commun. 2020 Jul 14;11(1):3525. doi: 10.1038/s41467-020-17231-3.
Copper electrocatalysts have been shown to selectively reduce carbon dioxide to hydrocarbons. Nevertheless, the absence of a systematic study based on time-resolved spectroscopy renders the functional agent-either metallic or oxidative Copper-for the selectivity still undecidable. Herein, we develop an operando seconds-resolved X-ray absorption spectroscopy to uncover the chemical state evolution of working catalysts. An oxide-derived Copper electrocatalyst is employed as a model catalyst to offer scientific insights into the roles metal states serve in carbon dioxide reduction reaction (CORR). Using a potential switching approach, the model catalyst can achieve a steady chemical state of half-Cu(0)-and-half-Cu(I) and selectively produce asymmetric C products - CHOH. Furthermore, a theoretical analysis reveals that a surface composed of Cu-Cu(I) ensembles can have dual carbon monoxide molecules coupled asymmetrically, which potentially enhances the catalyst's CORR product selectivity toward C products. Our results offer understandings of the fundamental chemical states and insights to the establishment of selective CORR.
铜电催化剂已被证明能选择性地将二氧化碳还原为碳氢化合物。然而，缺乏基于时间分辨光谱的系统研究使得对于选择性的功能剂（金属铜或氧化态铜）仍无法确定。在此，我们开发了一种原位秒级分辨X射线吸收光谱技术，以揭示工作催化剂的化学状态演变。采用氧化物衍生的铜电催化剂作为模型催化剂，以深入了解金属态在二氧化碳还原反应（CORR）中所起的作用。通过电位切换方法，该模型催化剂可实现半Cu(0)和半Cu(I)的稳定化学状态，并选择性地产生不对称C产物——CHOH。此外，理论分析表明，由Cu-Cu(I)组合构成的表面可使两个一氧化碳分子不对称耦合，这可能会提高催化剂对C产物的CORR产物选择性。我们的结果有助于理解基本化学状态，并为建立选择性CORR提供见解。
