摘要
在基于金属-半导体异质结构的等离激元介导化学反应中,了解其中的电荷转移和复合机制进而调控界面、提高界面电荷分离,对于提高等离激元催化反应效率至关重要。但电化学体系中固液界面上的等离激元光电催化反应是一个多过程、多时间尺度、多影响因素的复杂体系,光生载流子在界面间传递机制的研究仍面临着巨大的挑战。由于光电化学信号的产生和变化包含了诸多体相和界面过程,因此光电化学方法是探究等离激元催化反应过程中的界面电荷转移机制的有效手段之一。本文合成了TiO_(2)和Ag-TiO_(2)纳米粒子,以光电化学方法作为主要研究手段,并结合电化学和各种谱学表征手段,探究了电极陷阱态对界面电荷转移机制的影响。结果表明,在Ag负载在TiO_(2)表面后,电极的陷阱态显著增加。结合XPS以及PL光谱,陷阱态增加可主要归咎于表面羟基。陷阱态的增加导致了荧光的猝灭和光电响应的减弱,但增加的陷阱态复合过程也延长了载流子的寿命。陷阱态的调控必然会影响界面电荷转移,从而改变热载流子的数量和寿命,进而调控后续Ag界面上的等离激元反应。在反应位点位于金属的基于金属-半导体复合体系的等离激元催化反应中,认识到半导体陷阱态对于界面电荷转移的作用有助于在等离激元介导化学反应中更好地利用载流子、提高反应效率。
In the field of metal-semiconductor composites based plasmon-mediated chemical reactions,a clear and in-depth understanding of charge transfer and recombination mechanisms is crucial for improving plasmonic photocatalytic efficiency.However,the plasmonic photocatalytic reactions at the solid-liquid interface of the electrochemical systems involve complex processes with multiple elementary steps,multiple time scales,and multiple controlling factors.Herein,the combination of photoelectrochemical and electrochemical as well as spectroscopic characterizations has been successfully used to study the effects of traps on the photo-induced interfacial charge transfer of silver-titanium dioxide(Ag-TiO_(2)).The results show that the increase of surface hydroxyl groups may be the key reason leading to the increase of traps after the Ag deposition on the surface of TiO_(2).The increased traps of Ag-TiO_(2),including deep and shallow traps,subsequently lead to the quenching of fluorescence and the reduction of photocurrent in the UV region.But the enhanced trap recombination may also prolong the lifetime of carriers.The modulation of traps is bound to affect the interfacial charge transfer,and thus,change the amount and lifetime of hot carriers,which can be exploited to manipulate the molecular reactions at the Ag surface.Our work highlights the importance of traps at metalsemiconductor electrodes that may help utilize the hot carriers in plasmonic mediated chemical reactions.
作者
梁志豪
王家正
王丹
周剑章
吴德印
Zhi-Hao Liang;Jia-Zheng Wang;Dan Wang;Jian-Zhang Zhou;De-Yin Wu(State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering,Xiamen University,Xiamen,361005,Fujian,China)
出处
《电化学(中英文)》
CAS
北大核心
2023年第8期31-46,共16页
Journal of Electrochemistry
基金
supports from the National Natural Science Foundation of China(No.22032004)
the Ministry of Science and Technology of China(No.218YFC1602805).