Au-TiO_(2)光电极界面声子热输运特性的分子动力学模拟  

Molecular dynamics simulation of thermal transport properties of phonons at interface of Au-TiO_(2) photoelectrode

作　　者：桑丽霞[1] 李志康 Sang Li-Xia;Li Zhi-Kang(Beijing Key Laboratory of Heat Transfer and Energy Conversion,MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学,传热强化与过程节能教育部重点实验室,传热与能源利用北京市重点实验室,北京100124

出　　处：《物理学报》2024年第10期116-125,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:52176174)资助的课题。

摘　　要：为了研究光电分解水体系中具有热等离激元效应的Au-TiO_(2)电极的界面热输运特性,本文采用非平衡分子动力学方法研究了温度、界面耦合强度以及添加石墨烯层对Au-TiO_(2)界面热导的影响,并通过声子态密度对界面热导的变化进行了分析.研究结果表明,当体系温度从300 K增加到800 K时,Au-TiO_(2)界面导热系数增加了78.55%,这与更多的低频声子参与界面热输运相关,更多的热量传递到TiO_(2)上可促进界面反应.随着Au与TiO_(2)界面耦合强度的增大,界面热导率可通过TiO_(2)和Au的声子态密度的重叠程度得到优化.添加单层石墨烯可提高Au-TiO_(2)结构的界面热导,其中0—30 THz的低频区声子对导热贡献最大,但添加2层和3层石墨烯,石墨烯层与层之间的相互作用力阻碍了界面传热,且在低频区的声子数量有所降低,不利于热量在Au和TiO_(2)之间进行传递.Thermoplasmonics originating from the relaxation process of plasmon resonances in nanostructures can be utilized as an efficient and highly localized heat source in solar-hydrogen conversion,but there have been few researches on the interfacial heat transport properties of photoelectrode with the thermoplasmonics effect in a photoelectrochemical water splitting system.In this work,the effects of temperature,interfacial coupling strength and the addition of graphene layers on the interfacial thermal conductance of Au-TiO_(2) electrodes are investigated by the non-equilibrium molecular dynamics simulation,and the variation of interfacial thermal conductance is analyzed by the phonon density of states.The results show that the interfacial thermal conductivity is increased by 78.55%when the temperature increases from 300 to 800 K.This is related to the fact that more low-frequency phonons participate in the interface heat transport,allowing more heat to be transferred to TiO2 to promote the interface reaction.As the coupling strength of the Au-TiO_(2) interface increases,the interfacial thermal conductivity of the electrode increases and then tends to stabilize.The interfacial thermal conductivity can be optimized by increasing the degree of overlap of the phonon state densities of Au and TiO_(2).The addition of a single layer of graphene can increase the interfacial thermal conductivity to 98.072 MW·m^(-2)·K^(-1),but the addition of 2 and 3 layers of graphene can hinder interfacial heat transfer in Au and TiO_(2) due to the interaction between the layers of graphene.When adding graphene layer,medium-frequency phonons and high-frequency phonons are stimulated to participate in the interfacial heat transfer,but with the increase of the graphene layers,the number of low-frequency phonons in a range of 0-30 THz decreases,and these low-frequency phonons make the greatest contribution to the interfacial thermal conductivity.The obtained results are useful in regulating the thermal transport properties of the photoelectr

关 键 词：Au-TiO_(2) 界面热导 声子态密度 分子动力学 

分 类 号：O643.1[理学—物理化学]