일  시 : 2024년 3월 28일(목) 오후 4시 30분

Hetero-diatomic sites for photocatalytic C – C coupling: Mechanistic understanding of reaction mechanisms

Tae Kyu Kim

Department of Chemistry, Korea Advanced Institute of Science and Technology

Daejeon 34141, Republic of Korea

While diatomic-site catalysts (DAC) have garnered tremendous attention for selective CO₂ photoreduction, the diatomic-type effect on the product selectivity is severely neglected in dual-atom catalysis, especially in the thermodynamical and kinetical mechanism of CO₂ to C₂₊ products. In this presentation, we present our recent approach to fabricate covalent organic framework (COF) based DAC photocatalysts, and to elucidate related photocatalytic reaction mechanisms. We first engineered a novel Zn-porphyrin/RuCu-pincer complex DAC (ZnPor-RuCuDAC) by cross-organizing dual-atom sites into a COF. Under light illumination, heteronuclear ZnPor-RuCuDAC exhibited the best acetate selectivity (95.1%) with an average rate of 400.5 μmol g⁻¹ h⁻¹, while the homoatomic counterparts presented the best CO selectivity. A series of in-situ spectroscopic analyses revealed that the heteronuclear Ru–Cu sites easily appear as C–C coupling intermediates. Detailed theoretical calculations confirmed that due to the strong gradient orbital coupling caused by the Ru 4d–Cu 3d orbital resonance, two formed *CO intermediates of the heteroatom showed a significantly weaker electrostatic repulsion for an asymmetric charge distribution, which resulted from a side-to-side absorption and narrow dihedral angle distortion. Our approach provides a crucial perspective on the symmetry-forbidden coupling mechanism of C₁ intermediates on DACs.

* 졸업논문 교과목 수강자 세미나 필수 참석 안내
석사, 석박통합, 박사과정이 수강하는 <졸업논문연구학점 1~6>수강자는 학과에서 개최하는 목요일 정규세미나에 반드시 참석해야함.

관련공지(skku.edu)https://skb.skku.edu/chem/News/notice.do?mode=view&articleNo=146936&article.offset=10&articleLimit=10)