通过扫描光电化学显微镜研究超分子光敏剂-二氧化钛薄膜系统的光诱导电子转移  

Scanning Photoelectrochemical Microscopic Study in Photoinduced Electron Transfer of Supramolecular Sensitizers-TiO_(2)Thin Films Systems

作　　者：张生雅 姚敏 王泽 刘天娇 张蓉芳 叶慧琴 冯彦俊 卢小泉 Sheng-Ya Zhang;Min Yao;Ze Wang;Tian-Jiao Liu;Rong-Fang Zhang;Hui-Qin Ye;Yan-Jun Feng;Xiao-Quan Lu(Key Laboratory of Bioelectrochemistry&Environmental Analysis of Gansu Province,College of Chemistry&Chemical Engineering,Northwest Normal University,Lanzhou,730070,PR Chin)

机构地区：[1]西北师范大学化学化工学院,甘肃省生物电化学与环境分析重点实验室,甘肃兰州730030

出　　处：《电化学》2023年第6期65-76,共12页Journal of Electrochemistry

基　　金：We are thankful to the National Natural Science Foundation of China(22174110 and 22127803);the Industrial Support Plan of Gansu Provincial Department of Education(2021cyzc-01);the Special Fund Project for Guiding Local Scientific and Technological Development by the Central Government(2020-2060503-17).

摘　　要：在基于TiO_(2)的光阳极上枝接电荷转移通道仍然是太阳能到化学转换技术的一个迫切瓶颈。尽管进行了大量的尝试,但TiO_(2)作为有前途的光阳极材料仍然受到电荷传输动力学迟缓的影响。因此,一种组装策略涉及将金属卟啉基光敏剂分子(MP)轴向配位嫁接到表面改性的TiO_(2)纳米棒(TiO_(2)NRs)光阳极上,形成复合MP/TiO_(2)NRs光电极。正如预期的那样,与单独的TiO_(2)NR和MPA/TiO_(2)NRs光电极相比,所得到的独特的MPB/TiO_(2)NRs光电极具有明显提高的光电流密度。采用扫描光电化学显微镜(SPECM)和强度调制光电流光谱(IMPS)系统地评估了MP/TiO_(2)NRs光电极的连续光激发电子转移(PET)动力学信息。通过数据拟合发现,在光照条件下,MPB/TiO_(2)NRs的光电子转移速率(keff)常数比纯TiO_(2)NRs高2.6倍左右。MPB/TiO_(2)NRs的高动力学常数是由于D-A结构的共轭分子MPB可以有效地加速分子内电子转移,以及促进电子在新型电荷转移通道中参与I3-到I的还原反应。本研究展示的结果有望为研究人工光合作用电荷转移过程的机制和构建高效的光电极提供一些启发。Crafting charge transfer channels at titanium dioxide(TiO_(2))based photoanodes remain a pressing bottleneck in solar-to-chemical conversion technology.Despite the tremendous attempts,TiO_(2)as the promising photoanode material still suffers from sluggish charge transport kinetics.Herein,we propose an assembly strategy that involves the axial coordination grafting metalloporphyrin-based photosensitizer molecules(MP)onto the surface-modified TiO_(2)nanorods(NRs)photoanode,forming the composite MP/TiO_(2)NRs photoelectrode.As expected,the resulted unique MPB/TiO_(2)NRs photoelectrode displays significantly improved photocurrent density as compared to TiO_(2)NRs alone and MPA/TiO_(2)NRs photoelectrode.Scanning photoelectrochemical microscopy(SPECM)and intensity modulated photocurrent spectroscopy(IMPS)were employed to systematically evaluate the continuous photoinduced electron transfer(PET)dynamics for MP/TiO_(2)NRs photoelectrode.According to the data fitting,it is found that the photoelectron transfer rate(keff)constant for the MPB/TiO_(2)NRs is about 2.6 times higher than that for the pure TiO_(2)NRs under light irradiation.The high kinetic constant for the MPB/TiO_(2)NRs was ascribed to that the conjugated molecules MPB of D-A structure can effectively accelerate intramolecular electrons transfer as well as promote electrons taking part in the reduction reaction of I3to Iin the novel charge transfer channel.The results demonstrated in this study are expected to shed some light on investigating the mechanism in the charge transfer process of artificial photosynthesis and constructing efficient photoelectrodes.

关 键 词：光敏剂 TiO_(2)纳米棒 扫描光电化学显微镜 光激发电子转移 

分 类 号：O646.5[理学—物理化学]