Department of Chemistry, School of Science, Tokyo Institute of Technology , 2-12-1-NE-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
Graduate School of Engineering, Toyota Technological Institute , 2-12-1 Hisakata, Tempaku, Nagoya 468-8511, Japan.
ACS Appl Mater Interfaces. 2017 Jul 19;9(28):23869-23877. doi: 10.1021/acsami.7b07484. Epub 2017 Jul 7.
Metal-complex/semiconductor hybrids have attracted attention as photocatalysts for visible-light CO reduction, and electron transfer from the metal complex to the semiconductor is critically important to improve the performance. Here rutile TiO nanoparticles having 5-10 nm in size were employed as modifiers to improve interfacial charge transfer between semiconducting carbon nitride nanosheets (NS-CN) and a supramolecular Ru(II)-Re(I) binuclear complex (RuRe). The RuRe/TiO/NS-CN hybrid was capable of photocatalyzing CO reduction into CO with high selectivity under visible light (λ > 400 nm), outperforming an analogue without TiO by a factor of 4, in terms of both CO formation rate and turnover number (TON). The enhanced photocatalytic activity was attributed primarily to prolonged lifetime of free and/or shallowly trapped electrons generated in TiO/NS-CN under visible-light irradiation, as revealed by transient absorption spectroscopy. Experimental results also indicated that the TiO modifier served as a good adsorption site for RuRe, which resulted in the suppression of undesirable desorption of the complex, thereby contributing to the improved photocatalytic performance. This study presents the first successful example of interfacial manipulation in a metal-complex/semiconductor hybrid photocatalyst for improved visible-light CO reduction to produce CO.
金属配合物/半导体杂化材料作为可见光 CO 还原的光催化剂引起了人们的关注，而金属配合物向半导体的电子转移对于提高其性能至关重要。在本研究中，我们采用 5-10nm 尺寸的锐钛矿 TiO 纳米粒子作为修饰剂，以改善半导体氮化碳纳米片（NS-CN）与超分子 Ru(II)-Re(I)双核配合物（RuRe）之间的界面电荷转移。与没有 TiO 的类似物相比，RuRe/TiO/NS-CN 杂化材料在可见光（λ>400nm）照射下能够将 CO 选择性地催化还原为 CO，其 CO 形成速率和周转数（TON）分别提高了 4 倍。通过瞬态吸收光谱，我们发现这一增强的光催化活性主要归因于 TiO/NS-CN 中在可见光照射下生成的自由和/或浅陷阱电子的寿命延长。实验结果还表明，TiO 修饰剂是 RuRe 的良好吸附位点，这抑制了配合物的不期望解吸，从而提高了光催化性能。本研究首次成功地在金属配合物/半导体杂化光催化剂中进行了界面调控，以提高可见光 CO 还原为 CO 的效率。
