Operando time-resolved X-ray absorption spectroscopy reveals the chemical nature enabling highly selective CO2 reduction

• Published in: Nature communications 2020-07, Vol.11 (1), p.3525-3525, Article 3525
• Main Authors: 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
• Format: Article
• Language: English
• Subjects: 639/638/161; 639/638/298; 639/638/675; Absorption spectroscopy; Asymmetry; Carbon dioxide; Carbon monoxide; Catalysts; Chemical reduction; Copper; Electrocatalysts; Evolution; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary); Selectivity; Spectrum analysis; Theoretical analysis; X ray absorption; X-ray absorption spectroscopy; X-ray spectroscopy
• ISSN: 2041-1723; 2041-1723
• 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 (CO 2 RR). 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 2 products - C 2 H 5 OH. 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 CO 2 RR product selectivity toward C 2 products. Our results offer understandings of the fundamental chemical states and insights to the establishment of selective CO 2 RR. A systematic time-resolved study can provide key insights on selective carbon dioxide electro-reduction. Here, the authors report operando seconds-resolved X-ray absorption spectroscopy to uncover the chemical state evolution of working catalysts in a carbon dioxide electroreduction process.