Feng Yiyu, Liu Hongpo, Luo Wen, Liu Enzuo, Zhao Naiqin, Yoshino Katsumi, Feng Wei
School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072, China.
Sci Rep. 2013 Nov 19;3:3260. doi: 10.1038/srep03260.
Reduced graphene oxide-azobenzene (RGO-AZO) hybrids were prepared via covalent functionalization for long-term solar thermal storage. Thermal barrier (ΔEa) of cis to tran reversion and thermal storage (ΔH) were improved by molecular hydrogen bonds (H-bonds) through ortho- or para-substitution of AZO. Intramolecular H-bonds thermally stabilized cis-ortho-AZO on RGO with a long-term half-life of 5400 h (ΔEa = 1.2 eV), which was much longer than that of RGO-para-AZO (116 h). RGO-para-AZO with one intermolecular H-bond showed a high density of thermal storage up to 269.8 kJ kg(-1) compared with RGO-ortho-AZO (149.6 kJ kg(-1)) with multiple intra- and intermolecular H-bonds of AZO according to relaxed stable structures. Thermal storage in experiment was the same order magnitude to theoretical data based on ΔH calculated by density functional theory and packing density. Photoactive RGO-AZO hybrid can be developed for high-performance solar thermal storage by optimizing molecular H-bonds.
通过共价功能化制备了用于长期太阳能热存储的还原氧化石墨烯-偶氮苯（RGO-AZO）杂化物。通过偶氮苯的邻位或对位取代形成的分子氢键（H键）提高了顺式到反式转化的热垒（ΔEa）和热存储（ΔH）。分子内氢键使RGO上的顺式邻位偶氮苯热稳定，半衰期长达5400小时（ΔEa = 1.2 eV），远长于RGO-对位偶氮苯（116小时）。与具有多个偶氮苯分子内和分子间氢键的RGO-邻位偶氮苯（149.6 kJ kg(-1)）相比，具有一个分子间氢键的RGO-对位偶氮苯显示出高达269.8 kJ kg(-1)的高密度热存储。根据松弛稳定结构，实验中的热存储与基于密度泛函理论计算的ΔH和堆积密度的理论数据处于同一数量级。通过优化分子氢键，可以开发出用于高性能太阳能热存储的光活性RGO-AZO杂化物。
