Pt-Au双金属纳米马达能量转化效率的数值模拟研究

Numerical Simulation of Energy Conversion Efficiency of Pt-Au Bimetal Nanomotor

微纳米马达的能量转化效率(η)对其应用能力具有决定性作用。通过建立Pt-Au双金属纳米马达的二维轴对称模型,利用有限元仿真软件COMSOL Multiphysics对马达自电泳运动进行数值模拟,研究了马达自身形状和组成以及溶液电导率对η的影响规律。结果表明:对于体积一定的不同形状轴对称Pt-Au双金属马达,其几何损耗率即中心半径RC与两端半径RE之差与RC的比值越小,η越高;若固定该比值,则RC越小,η越高;改变双金属马达中的Pt-Au比例(LPt/LPt-Au),当0.27<LPt/LPt-Au<0.9时,η先持续增大后急剧衰减,且在LPt/LPt-Au介于0.8~0.875之间达到最大值;马达在电解质溶液中的运动受到限制,且η随溶液电导率的提高而降低。文中模拟结果与实验数据较为吻合,能为该类微纳米马达的设计、制备和应用提供理论指导。

The energy conversion efficiency(η)of micro/nanomotor plays a decisive role in its application ability.In this paper,by establishing a two-dimensional axisymmetric model of the Pt-Au bimetallic nanomotor,a finite element simulation software COMSOL multiphysics was used to numerically simulate the self-electrophoretic motion of the motor and study the influences of shape,compositions,and the solution conductivity onη.The experimental results show that for axisymmetric Pt-Au bimetal nanomotors of a certain volume with different shapes,the smaller the geometric loss rate of the motor,that is,the ratio of the difference between the center radius RCand the radius REat both ends to the RC,the higher theη;if the ratio is the same,then the smaller the RC,the higher theη;changing the Pt-Au ratio in the bimetal motor(LPt/LPt-Au),when 0.27<LPt/LPt-Au<0.9,ηkeeps increasing first and then sharply decays,and reaches the maximum between LPt/LPt-Au=0.8~0.875;the movement of the motor is limited in the electrolyte solution,andηdecreases as the solution conductivity increases.The simulation results here are in good agreement with the experimental data,which can provide theoretical guidance for the design,fabrication and application of this type of motor.