Theoretical Insights into the Impact of Ru Catalyst Anchors on the Efficiency of Photocatalytic CO2 Reduction on Ta2O5

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• 作者：Alexey V. Akimov ; R. Jinnouchi ; S. Shirai ; R. Asahi ; Oleg V. Prezhdo
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：7186-7197
• 全文大小：511K
• ISSN：1520-5207

文摘

We present a computational study of the dynamical and electronic structure origins of the impact of anchoring groups, PO₃H₂, COOH, and OH, on the efficiency of photochemical CO₂ reduction in Ru(di-X-bpy)(CO)₂Cl₂/Ta₂O₅ systems. Recent experimental studies indicate that the efficiency may not directly correlate with the driving force for electron transfer (ET) in these systems, prompting the need for further investigation of the role of anchor groups. Our analysis shows that there are at least two key roles of the anchor in determining the efficiency of CO₂ reduction by the Ru complex. First, depending on local steric interactions, different tilting angles and their fluctuations may emerge for different anchors, affecting the magnitude of the donor鈥揳cceptor coupling. Second, depending on localization of acceptor states on the anchor, determined by the anchor鈥檚 tendency to form conjugate subsystems, the yields of ET to the catalytic center may vary, directly affecting the photocatalytic efficiency. Finally, our calculations indicate that surface modeling with N-doping and many-body effects are needed to describe the ET process in the systems properly. N-doping imparts the Ta₂O₅ surface with a dipole moment, while Coulomb and exchange contributions to the electron鈥揾ole interaction can produce excitons that should be taken into account.